diff --git a/doc/pub/week37/html/._week37-bs015.html b/doc/pub/week37/html/._week37-bs015.html
index 23ddf7aec..3d2fc7b18 100644
--- a/doc/pub/week37/html/._week37-bs015.html
+++ b/doc/pub/week37/html/._week37-bs015.html
@@ -316,7 +316,7 @@ $$
 p(\boldsymbol{\beta}\vert\boldsymbol{D})\propto p(\boldsymbol{D}\vert\boldsymbol{\beta})p(\boldsymbol{\beta}).
 $$
 
-<p>We have a model for \( p(\boldsymbol{D}\vert\boldsymbol{\beta}) \) but need one for the <b>prior</b> \( p(\boldsymbol{\beta} \)!   </p>
+<p>We have a model for \( p(\boldsymbol{D}\vert\boldsymbol{\beta}) \) but need one for the <b>prior</b> \( p(\boldsymbol{\beta}) \)!   </p>
 
 <p>
 <!-- navigation buttons at the bottom of the page -->
diff --git a/doc/pub/week37/html/._week37-bs030.html b/doc/pub/week37/html/._week37-bs030.html
index b32a69ff2..c0af19a83 100644
--- a/doc/pub/week37/html/._week37-bs030.html
+++ b/doc/pub/week37/html/._week37-bs030.html
@@ -302,11 +302,11 @@ unknown parameter such as the parameters \( \boldsymbol{\beta} \) from linear re
 \( \mathbb{E}(\boldsymbol{\beta}) = \boldsymbol{\beta} \), which means that the estimator of the regression parameters is unbiased.
 </p>
 
-<p>We found also that the variance of the estimate of the \( j \)-th regression coefficient is
+<p>In the exercises this week we show that the variance of the estimate of the \( j \)-th regression coefficient is
 \( \boldsymbol{\sigma}^2 (\boldsymbol{\beta}_j ) = \boldsymbol{\sigma}^2 [(\mathbf{X}^{T} \mathbf{X})^{-1}]_{jj}  \).
 </p>
 
-<p>This quantity will be used to
+<p>This quantity can be used to
 construct a confidence interval for the estimates.
 </p>
 
diff --git a/doc/pub/week37/html/week37-reveal.html b/doc/pub/week37/html/week37-reveal.html
index fe273f13a..ed598f6d3 100644
--- a/doc/pub/week37/html/week37-reveal.html
+++ b/doc/pub/week37/html/week37-reveal.html
@@ -578,7 +578,7 @@ p(\boldsymbol{\beta}\vert\boldsymbol{D})\propto p(\boldsymbol{D}\vert\boldsymbol
 $$
 <p>&nbsp;<br>
 
-<p>We have a model for \( p(\boldsymbol{D}\vert\boldsymbol{\beta}) \) but need one for the <b>prior</b> \( p(\boldsymbol{\beta} \)!   </p>
+<p>We have a model for \( p(\boldsymbol{D}\vert\boldsymbol{\beta}) \) but need one for the <b>prior</b> \( p(\boldsymbol{\beta}) \)!   </p>
 </section>
 
 <section>
@@ -998,11 +998,11 @@ unknown parameter such as the parameters \( \boldsymbol{\beta} \) from linear re
 \( \mathbb{E}(\boldsymbol{\beta}) = \boldsymbol{\beta} \), which means that the estimator of the regression parameters is unbiased.
 </p>
 
-<p>We found also that the variance of the estimate of the \( j \)-th regression coefficient is
+<p>In the exercises this week we show that the variance of the estimate of the \( j \)-th regression coefficient is
 \( \boldsymbol{\sigma}^2 (\boldsymbol{\beta}_j ) = \boldsymbol{\sigma}^2 [(\mathbf{X}^{T} \mathbf{X})^{-1}]_{jj}  \).
 </p>
 
-<p>This quantity will be used to
+<p>This quantity can be used to
 construct a confidence interval for the estimates.
 </p>
 </section>
diff --git a/doc/pub/week37/html/week37-solarized.html b/doc/pub/week37/html/week37-solarized.html
index 6a8709ace..5a13d9675 100644
--- a/doc/pub/week37/html/week37-solarized.html
+++ b/doc/pub/week37/html/week37-solarized.html
@@ -577,7 +577,7 @@ $$
 p(\boldsymbol{\beta}\vert\boldsymbol{D})\propto p(\boldsymbol{D}\vert\boldsymbol{\beta})p(\boldsymbol{\beta}).
 $$
 
-<p>We have a model for \( p(\boldsymbol{D}\vert\boldsymbol{\beta}) \) but need one for the <b>prior</b> \( p(\boldsymbol{\beta} \)!   </p>
+<p>We have a model for \( p(\boldsymbol{D}\vert\boldsymbol{\beta}) \) but need one for the <b>prior</b> \( p(\boldsymbol{\beta}) \)!   </p>
 
 <!-- !split --><br><br><br><br><br><br><br><br><br><br>
 <h2 id="ridge-and-bayes">Ridge and Bayes </h2>
@@ -944,11 +944,11 @@ unknown parameter such as the parameters \( \boldsymbol{\beta} \) from linear re
 \( \mathbb{E}(\boldsymbol{\beta}) = \boldsymbol{\beta} \), which means that the estimator of the regression parameters is unbiased.
 </p>
 
-<p>We found also that the variance of the estimate of the \( j \)-th regression coefficient is
+<p>In the exercises this week we show that the variance of the estimate of the \( j \)-th regression coefficient is
 \( \boldsymbol{\sigma}^2 (\boldsymbol{\beta}_j ) = \boldsymbol{\sigma}^2 [(\mathbf{X}^{T} \mathbf{X})^{-1}]_{jj}  \).
 </p>
 
-<p>This quantity will be used to
+<p>This quantity can be used to
 construct a confidence interval for the estimates.
 </p>
 
diff --git a/doc/pub/week37/html/week37.html b/doc/pub/week37/html/week37.html
index f556b5340..93e88c43a 100644
--- a/doc/pub/week37/html/week37.html
+++ b/doc/pub/week37/html/week37.html
@@ -654,7 +654,7 @@ $$
 p(\boldsymbol{\beta}\vert\boldsymbol{D})\propto p(\boldsymbol{D}\vert\boldsymbol{\beta})p(\boldsymbol{\beta}).
 $$
 
-<p>We have a model for \( p(\boldsymbol{D}\vert\boldsymbol{\beta}) \) but need one for the <b>prior</b> \( p(\boldsymbol{\beta} \)!   </p>
+<p>We have a model for \( p(\boldsymbol{D}\vert\boldsymbol{\beta}) \) but need one for the <b>prior</b> \( p(\boldsymbol{\beta}) \)!   </p>
 
 <!-- !split --><br><br><br><br><br><br><br><br><br><br>
 <h2 id="ridge-and-bayes">Ridge and Bayes </h2>
@@ -1021,11 +1021,11 @@ unknown parameter such as the parameters \( \boldsymbol{\beta} \) from linear re
 \( \mathbb{E}(\boldsymbol{\beta}) = \boldsymbol{\beta} \), which means that the estimator of the regression parameters is unbiased.
 </p>
 
-<p>We found also that the variance of the estimate of the \( j \)-th regression coefficient is
+<p>In the exercises this week we show that the variance of the estimate of the \( j \)-th regression coefficient is
 \( \boldsymbol{\sigma}^2 (\boldsymbol{\beta}_j ) = \boldsymbol{\sigma}^2 [(\mathbf{X}^{T} \mathbf{X})^{-1}]_{jj}  \).
 </p>
 
-<p>This quantity will be used to
+<p>This quantity can be used to
 construct a confidence interval for the estimates.
 </p>
 
diff --git a/doc/pub/week37/ipynb/ipynb-week37-src.tar.gz b/doc/pub/week37/ipynb/ipynb-week37-src.tar.gz
index 71987d156..5a8c788c4 100644
Binary files a/doc/pub/week37/ipynb/ipynb-week37-src.tar.gz and b/doc/pub/week37/ipynb/ipynb-week37-src.tar.gz differ
diff --git a/doc/pub/week37/ipynb/week37.ipynb b/doc/pub/week37/ipynb/week37.ipynb
index 14c096c3e..c24beccbd 100644
--- a/doc/pub/week37/ipynb/week37.ipynb
+++ b/doc/pub/week37/ipynb/week37.ipynb
@@ -2,7 +2,7 @@
  "cells": [
   {
    "cell_type": "markdown",
-   "id": "6d380d95",
+   "id": "7c0ddab1",
    "metadata": {
     "editable": true
    },
@@ -14,7 +14,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "1b387d27",
+   "id": "6c033bf4",
    "metadata": {
     "editable": true
    },
@@ -29,7 +29,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "faf4e906",
+   "id": "e4cd5fa1",
    "metadata": {
     "editable": true
    },
@@ -59,7 +59,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "b47b616f",
+   "id": "bf80a276",
    "metadata": {
     "editable": true
    },
@@ -81,7 +81,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "4ba4f463",
+   "id": "0e1f0a90",
    "metadata": {
     "editable": true
    },
@@ -91,7 +91,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "7033032b",
+   "id": "1b290d64",
    "metadata": {
     "editable": true
    },
@@ -114,7 +114,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "72507184",
+   "id": "ceed3a82",
    "metadata": {
     "editable": true
    },
@@ -126,7 +126,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "7123664e",
+   "id": "1d7e8f98",
    "metadata": {
     "editable": true
    },
@@ -139,7 +139,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "c149ed84",
+   "id": "58722d7d",
    "metadata": {
     "editable": true
    },
@@ -151,7 +151,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e30ac9c6",
+   "id": "45120edc",
    "metadata": {
     "editable": true
    },
@@ -163,7 +163,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "6815bea2",
+   "id": "4f3b680a",
    "metadata": {
     "editable": true
    },
@@ -175,7 +175,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "bf97703b",
+   "id": "08489797",
    "metadata": {
     "editable": true
    },
@@ -186,7 +186,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e7969670",
+   "id": "a1c81f06",
    "metadata": {
     "editable": true
    },
@@ -198,7 +198,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "ab8ea399",
+   "id": "4e092776",
    "metadata": {
     "editable": true
    },
@@ -209,7 +209,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "037bc143",
+   "id": "79e5358a",
    "metadata": {
     "editable": true
    },
@@ -221,7 +221,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "4efd42ab",
+   "id": "e5a4f865",
    "metadata": {
     "editable": true
    },
@@ -231,7 +231,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "70579324",
+   "id": "10b81ba7",
    "metadata": {
     "editable": true
    },
@@ -262,7 +262,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "339edfcc",
+   "id": "3349cb27",
    "metadata": {
     "editable": true
    },
@@ -274,7 +274,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "cf7096a5",
+   "id": "0fd1502e",
    "metadata": {
     "editable": true
    },
@@ -286,7 +286,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "94033507",
+   "id": "43cba0e8",
    "metadata": {
     "editable": true
    },
@@ -296,7 +296,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "deba34c1",
+   "id": "d6f4e7dc",
    "metadata": {
     "editable": true
    },
@@ -308,7 +308,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "6262ba5e",
+   "id": "50c2d673",
    "metadata": {
     "editable": true
    },
@@ -318,7 +318,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "0619240a",
+   "id": "30315a10",
    "metadata": {
     "editable": true
    },
@@ -330,7 +330,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "b75686c6",
+   "id": "fd8cdf51",
    "metadata": {
     "editable": true
    },
@@ -340,7 +340,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "3b6aa374",
+   "id": "7323296b",
    "metadata": {
     "editable": true
    },
@@ -352,7 +352,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "5a81c3ba",
+   "id": "e21334ab",
    "metadata": {
     "editable": true
    },
@@ -362,7 +362,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "798940d6",
+   "id": "82974124",
    "metadata": {
     "editable": true
    },
@@ -382,7 +382,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "3e3db132",
+   "id": "e053e43c",
    "metadata": {
     "editable": true
    },
@@ -394,7 +394,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "5a604a68",
+   "id": "94098e13",
    "metadata": {
     "editable": true
    },
@@ -404,7 +404,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "666e26b6",
+   "id": "27625b1f",
    "metadata": {
     "editable": true
    },
@@ -416,7 +416,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "f8251990",
+   "id": "8f3cc8b4",
    "metadata": {
     "editable": true
    },
@@ -428,7 +428,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "3b66f16c",
+   "id": "d7d5464d",
    "metadata": {
     "editable": true
    },
@@ -440,7 +440,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "baf49e5b",
+   "id": "c292afee",
    "metadata": {
     "editable": true
    },
@@ -452,7 +452,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e4ecd951",
+   "id": "cdbbd444",
    "metadata": {
     "editable": true
    },
@@ -464,7 +464,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "13f63b94",
+   "id": "100a8014",
    "metadata": {
     "editable": true
    },
@@ -476,7 +476,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "91dd808e",
+   "id": "d2e40c4d",
    "metadata": {
     "editable": true
    },
@@ -488,7 +488,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "77ad4e21",
+   "id": "1e48456e",
    "metadata": {
     "editable": true
    },
@@ -500,7 +500,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "a8e0e1d1",
+   "id": "38ced5b6",
    "metadata": {
     "editable": true
    },
@@ -510,7 +510,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "fe862804",
+   "id": "1163c07b",
    "metadata": {
     "editable": true
    },
@@ -522,7 +522,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "ade7ea17",
+   "id": "becc087f",
    "metadata": {
     "editable": true
    },
@@ -532,7 +532,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "4ad32e53",
+   "id": "5ca2b09d",
    "metadata": {
     "editable": true
    },
@@ -551,7 +551,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "db8a4e81",
+   "id": "6572c77d",
    "metadata": {
     "editable": true
    },
@@ -572,7 +572,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "2eae7d3c",
+   "id": "2a3f65e5",
    "metadata": {
     "editable": true
    },
@@ -584,7 +584,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "1fa9f97f",
+   "id": "2d264f77",
    "metadata": {
     "editable": true
    },
@@ -595,7 +595,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "577f4c39",
+   "id": "06b8a13c",
    "metadata": {
     "editable": true
    },
@@ -608,7 +608,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "3c9cc1df",
+   "id": "6d958ed3",
    "metadata": {
     "editable": true
    },
@@ -620,7 +620,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "6b584f04",
+   "id": "6330f3f2",
    "metadata": {
     "editable": true
    },
@@ -630,7 +630,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "425f2dd6",
+   "id": "ed6a9f67",
    "metadata": {
     "editable": true
    },
@@ -642,7 +642,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "548773f6",
+   "id": "de42ab8a",
    "metadata": {
     "editable": true
    },
@@ -652,7 +652,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "5fd041fe",
+   "id": "4f36b126",
    "metadata": {
     "editable": true
    },
@@ -664,7 +664,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "ad88bc06",
+   "id": "0a7eef00",
    "metadata": {
     "editable": true
    },
@@ -674,7 +674,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "cf96664b",
+   "id": "29940f94",
    "metadata": {
     "editable": true
    },
@@ -688,7 +688,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "2c2284fa",
+   "id": "f2204679",
    "metadata": {
     "editable": true
    },
@@ -700,7 +700,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "84e29408",
+   "id": "d3f4597f",
    "metadata": {
     "editable": true
    },
@@ -710,7 +710,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "3078b452",
+   "id": "c9e9ca01",
    "metadata": {
     "editable": true
    },
@@ -722,7 +722,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "4f03135a",
+   "id": "1c3062b6",
    "metadata": {
     "editable": true
    },
@@ -732,7 +732,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "53bea713",
+   "id": "b455f707",
    "metadata": {
     "editable": true
    },
@@ -744,7 +744,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "398cf6e0",
+   "id": "5ac8fdd3",
    "metadata": {
     "editable": true
    },
@@ -754,7 +754,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "8125280c",
+   "id": "827927db",
    "metadata": {
     "editable": true
    },
@@ -766,17 +766,17 @@
   },
   {
    "cell_type": "markdown",
-   "id": "a10353ef",
+   "id": "0c740a13",
    "metadata": {
     "editable": true
    },
    "source": [
-    "We have a model for $p(\\boldsymbol{D}\\vert\\boldsymbol{\\beta})$ but need one for the **prior** $p(\\boldsymbol{\\beta}$!"
+    "We have a model for $p(\\boldsymbol{D}\\vert\\boldsymbol{\\beta})$ but need one for the **prior** $p(\\boldsymbol{\\beta})$!"
    ]
   },
   {
    "cell_type": "markdown",
-   "id": "e494cd67",
+   "id": "a855fc3c",
    "metadata": {
     "editable": true
    },
@@ -792,7 +792,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "a812c8c9",
+   "id": "9dda8b9e",
    "metadata": {
     "editable": true
    },
@@ -804,7 +804,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "f037baa4",
+   "id": "d160205c",
    "metadata": {
     "editable": true
    },
@@ -814,7 +814,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e616de3b",
+   "id": "1b7501a6",
    "metadata": {
     "editable": true
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@@ -826,7 +826,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "af6da24a",
+   "id": "d75a8c65",
    "metadata": {
     "editable": true
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@@ -839,7 +839,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "4a7d0e04",
+   "id": "c9f718df",
    "metadata": {
     "editable": true
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@@ -851,7 +851,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e8439394",
+   "id": "b07b6425",
    "metadata": {
     "editable": true
    },
@@ -861,7 +861,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e498b7c0",
+   "id": "215a8730",
    "metadata": {
     "editable": true
    },
@@ -873,7 +873,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "53e1cdd8",
+   "id": "7013d0f0",
    "metadata": {
     "editable": true
    },
@@ -883,7 +883,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "b6773583",
+   "id": "d56b4ce0",
    "metadata": {
     "editable": true
    },
@@ -895,7 +895,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "4f88bb71",
+   "id": "f9c6b14d",
    "metadata": {
     "editable": true
    },
@@ -907,7 +907,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "5b9cbfcf",
+   "id": "0bde16cb",
    "metadata": {
     "editable": true
    },
@@ -917,7 +917,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "b51513bb",
+   "id": "0a2869fc",
    "metadata": {
     "editable": true
    },
@@ -929,7 +929,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "9d1f2849",
+   "id": "75b83b9b",
    "metadata": {
     "editable": true
    },
@@ -941,7 +941,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "b4f7eef2",
+   "id": "1e76d916",
    "metadata": {
     "editable": true
    },
@@ -953,7 +953,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "65d8734e",
+   "id": "09dfe26d",
    "metadata": {
     "editable": true
    },
@@ -963,7 +963,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "56739071",
+   "id": "4037962f",
    "metadata": {
     "editable": true
    },
@@ -975,7 +975,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e243dcd8",
+   "id": "39a85ba0",
    "metadata": {
     "editable": true
    },
@@ -985,7 +985,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "c7c497df",
+   "id": "b263a1fe",
    "metadata": {
     "editable": true
    },
@@ -1004,7 +1004,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "070287e3",
+   "id": "41730165",
    "metadata": {
     "editable": true
    },
@@ -1032,7 +1032,7 @@
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   {
    "cell_type": "markdown",
-   "id": "e22fa43a",
+   "id": "4076cee3",
    "metadata": {
     "editable": true
    },
@@ -1058,7 +1058,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "6475f9d9",
+   "id": "11139cb3",
    "metadata": {
     "editable": true
    },
@@ -1075,7 +1075,7 @@
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   {
    "cell_type": "markdown",
-   "id": "f2baba56",
+   "id": "b2bead9b",
    "metadata": {
     "editable": true
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@@ -1095,7 +1095,7 @@
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   {
    "cell_type": "markdown",
-   "id": "226a30bc",
+   "id": "8df8364e",
    "metadata": {
     "editable": true
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@@ -1124,7 +1124,7 @@
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   {
    "cell_type": "markdown",
-   "id": "4f7ccd9b",
+   "id": "6b5273f1",
    "metadata": {
     "editable": true
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@@ -1149,7 +1149,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "818dbc01",
+   "id": "a260b371",
    "metadata": {
     "editable": true
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@@ -1169,7 +1169,7 @@
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   {
    "cell_type": "markdown",
-   "id": "bf722f80",
+   "id": "2ff1e63c",
    "metadata": {
     "editable": true
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@@ -1181,7 +1181,7 @@
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   {
    "cell_type": "markdown",
-   "id": "a1fb098c",
+   "id": "ab4b2e8c",
    "metadata": {
     "editable": true
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@@ -1191,7 +1191,7 @@
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   {
    "cell_type": "markdown",
-   "id": "a46b6365",
+   "id": "85b6fb62",
    "metadata": {
     "editable": true
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@@ -1206,7 +1206,7 @@
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   {
    "cell_type": "markdown",
-   "id": "421dbac2",
+   "id": "42449344",
    "metadata": {
     "editable": true
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@@ -1219,7 +1219,7 @@
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   {
    "cell_type": "markdown",
-   "id": "e6c3206a",
+   "id": "35e4f511",
    "metadata": {
     "editable": true
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@@ -1232,7 +1232,7 @@
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   {
    "cell_type": "markdown",
-   "id": "f8d44482",
+   "id": "c787234f",
    "metadata": {
     "editable": true
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@@ -1244,7 +1244,7 @@
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   {
    "cell_type": "markdown",
-   "id": "c9d607d2",
+   "id": "183711dc",
    "metadata": {
     "editable": true
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@@ -1257,7 +1257,7 @@
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   {
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-   "id": "30f49f68",
+   "id": "2351078d",
    "metadata": {
     "editable": true
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@@ -1268,7 +1268,7 @@
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   {
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-   "id": "ce4ab2e6",
+   "id": "408ba3b5",
    "metadata": {
     "editable": true
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@@ -1282,7 +1282,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "67b80469",
+   "id": "3ea79849",
    "metadata": {
     "editable": true
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@@ -1292,7 +1292,7 @@
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   {
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-   "id": "7a50f0c2",
+   "id": "69439aad",
    "metadata": {
     "editable": true
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@@ -1306,7 +1306,7 @@
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   {
    "cell_type": "markdown",
-   "id": "d2954a4a",
+   "id": "e6c29fd8",
    "metadata": {
     "editable": true
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@@ -1319,7 +1319,7 @@
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   {
    "cell_type": "markdown",
-   "id": "bb9f82aa",
+   "id": "4bb52549",
    "metadata": {
     "editable": true
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@@ -1332,7 +1332,7 @@
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   {
    "cell_type": "markdown",
-   "id": "b6a78127",
+   "id": "3430d548",
    "metadata": {
     "editable": true
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@@ -1342,7 +1342,7 @@
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   {
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-   "id": "b55f6fdb",
+   "id": "9ba636b3",
    "metadata": {
     "editable": true
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@@ -1355,7 +1355,7 @@
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   {
    "cell_type": "markdown",
-   "id": "c372700a",
+   "id": "cb19e98f",
    "metadata": {
     "editable": true
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@@ -1365,7 +1365,7 @@
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   {
    "cell_type": "markdown",
-   "id": "def0177b",
+   "id": "3cc840d7",
    "metadata": {
     "editable": true
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@@ -1378,7 +1378,7 @@
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   {
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+   "id": "a5062213",
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     "editable": true
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@@ -1390,7 +1390,7 @@
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   {
    "cell_type": "markdown",
-   "id": "a38fcfbb",
+   "id": "8d555244",
    "metadata": {
     "editable": true
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@@ -1409,7 +1409,7 @@
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   {
    "cell_type": "markdown",
-   "id": "5524a735",
+   "id": "c4356604",
    "metadata": {
     "editable": true
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@@ -1422,7 +1422,7 @@
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   {
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-   "id": "ee8f7b06",
+   "id": "09dc08a1",
    "metadata": {
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@@ -1434,7 +1434,7 @@
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   {
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+   "id": "dab5056a",
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@@ -1447,7 +1447,7 @@
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   {
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-   "id": "fcd4707c",
+   "id": "8a1f8583",
    "metadata": {
     "editable": true
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@@ -1467,7 +1467,7 @@
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   {
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-   "id": "dd9a3fa4",
+   "id": "1be08ebb",
    "metadata": {
     "editable": true
    },
@@ -1481,16 +1481,16 @@
     "With the OLS expressions for the parameters $\\boldsymbol{\\beta}$ we found \n",
     "$\\mathbb{E}(\\boldsymbol{\\beta}) = \\boldsymbol{\\beta}$, which means that the estimator of the regression parameters is unbiased.\n",
     "\n",
-    "We found also that the variance of the estimate of the $j$-th regression coefficient is\n",
+    "In the exercises this week we show that the variance of the estimate of the $j$-th regression coefficient is\n",
     "$\\boldsymbol{\\sigma}^2 (\\boldsymbol{\\beta}_j ) = \\boldsymbol{\\sigma}^2 [(\\mathbf{X}^{T} \\mathbf{X})^{-1}]_{jj} $.\n",
     "\n",
-    "This quantity will be used to\n",
+    "This quantity can be used to\n",
     "construct a confidence interval for the estimates."
    ]
   },
   {
    "cell_type": "markdown",
-   "id": "85b9af40",
+   "id": "2a368353",
    "metadata": {
     "editable": true
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@@ -1505,7 +1505,7 @@
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   {
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-   "id": "71848370",
+   "id": "6fee4a1a",
    "metadata": {
     "editable": true
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@@ -1517,7 +1517,7 @@
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   {
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-   "id": "7dc480e2",
+   "id": "1a97c9ef",
    "metadata": {
     "editable": true
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@@ -1537,7 +1537,7 @@
   },
   {
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-   "id": "d503b401",
+   "id": "0a70afb2",
    "metadata": {
     "editable": true
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@@ -1557,7 +1557,7 @@
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   {
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-   "id": "5dc05a3a",
+   "id": "dc32eaea",
    "metadata": {
     "editable": true
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@@ -1581,7 +1581,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "1d7436f9",
+   "id": "016d0ab3",
    "metadata": {
     "editable": true
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@@ -1602,7 +1602,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "91de0653",
+   "id": "3f371f0d",
    "metadata": {
     "editable": true
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@@ -1632,7 +1632,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "cc286195",
+   "id": "abc56fe7",
    "metadata": {
     "editable": true
    },
@@ -1656,7 +1656,7 @@
   {
    "cell_type": "code",
    "execution_count": 1,
-   "id": "df694bc6",
+   "id": "a3d2885b",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -1695,7 +1695,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "8264314a",
+   "id": "5db67125",
    "metadata": {
     "editable": true
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@@ -1705,7 +1705,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "78ed6c76",
+   "id": "6f1b5417",
    "metadata": {
     "editable": true
    },
@@ -1716,7 +1716,7 @@
   {
    "cell_type": "code",
    "execution_count": 2,
-   "id": "ac6e56fc",
+   "id": "9d98136a",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -1736,7 +1736,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "5d1461c0",
+   "id": "c87eac4e",
    "metadata": {
     "editable": true
    },
@@ -1754,7 +1754,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "9240f787",
+   "id": "2f0f4313",
    "metadata": {
     "editable": true
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@@ -1766,7 +1766,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "cf71a1fa",
+   "id": "7895ee8b",
    "metadata": {
     "editable": true
    },
@@ -1783,7 +1783,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "bdeea008",
+   "id": "be454b28",
    "metadata": {
     "editable": true
    },
@@ -1795,7 +1795,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "ab9c658c",
+   "id": "7475f8f9",
    "metadata": {
     "editable": true
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@@ -1805,7 +1805,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "32bf29d7",
+   "id": "fd472029",
    "metadata": {
     "editable": true
    },
@@ -1817,7 +1817,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "03738e59",
+   "id": "b43c8f67",
    "metadata": {
     "editable": true
    },
@@ -1834,7 +1834,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "b3645289",
+   "id": "c47cfb6d",
    "metadata": {
     "editable": true
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@@ -1846,7 +1846,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "3ee442e8",
+   "id": "593188cd",
    "metadata": {
     "editable": true
    },
@@ -1856,7 +1856,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "13fe5164",
+   "id": "76de4d81",
    "metadata": {
     "editable": true
    },
@@ -1868,7 +1868,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "32402f78",
+   "id": "afc38c97",
    "metadata": {
     "editable": true
    },
@@ -1878,7 +1878,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "139dda79",
+   "id": "b0f2971c",
    "metadata": {
     "editable": true
    },
@@ -1890,7 +1890,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "14a798d4",
+   "id": "5a65e495",
    "metadata": {
     "editable": true
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@@ -1900,7 +1900,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "5f8f4fd6",
+   "id": "31419298",
    "metadata": {
     "editable": true
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@@ -1916,7 +1916,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "08ef40c3",
+   "id": "217ddd53",
    "metadata": {
     "editable": true
    },
@@ -1927,7 +1927,7 @@
   {
    "cell_type": "code",
    "execution_count": 3,
-   "id": "edf212c2",
+   "id": "ece05002",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -1992,7 +1992,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "6c4161ef",
+   "id": "de6dc4e2",
    "metadata": {
     "editable": true
    },
@@ -2003,7 +2003,7 @@
   {
    "cell_type": "code",
    "execution_count": 4,
-   "id": "1f8ec566",
+   "id": "da218205",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -2060,7 +2060,7 @@
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   {
    "cell_type": "markdown",
-   "id": "2d31584b",
+   "id": "5ea5df06",
    "metadata": {
     "editable": true
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@@ -2098,7 +2098,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "78838b5d",
+   "id": "40f41d74",
    "metadata": {
     "editable": true
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@@ -2109,7 +2109,7 @@
   {
    "cell_type": "code",
    "execution_count": 5,
-   "id": "e34a6467",
+   "id": "03bb50ae",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -2191,7 +2191,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "173f735d",
+   "id": "cd11e9fd",
    "metadata": {
     "editable": true
    },
@@ -2216,7 +2216,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "dfcf7c77",
+   "id": "6cf68ff2",
    "metadata": {
     "editable": true
    },
@@ -2244,7 +2244,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "6354796c",
+   "id": "c445bfb2",
    "metadata": {
     "editable": true
    },
@@ -2257,7 +2257,7 @@
   {
    "cell_type": "code",
    "execution_count": 6,
-   "id": "e28a2113",
+   "id": "8e26035a",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -2357,7 +2357,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "fc92ceab",
+   "id": "86a6b012",
    "metadata": {
     "editable": true
    },
@@ -2368,7 +2368,7 @@
   {
    "cell_type": "code",
    "execution_count": 7,
-   "id": "6fb8f658",
+   "id": "4a0e1afd",
    "metadata": {
     "collapsed": false,
     "editable": true
@@ -2457,7 +2457,7 @@
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   {
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-   "id": "14a95591",
+   "id": "bb1e0f15",
    "metadata": {
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@@ -2467,7 +2467,7 @@
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   {
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-   "id": "5e1dc46c",
+   "id": "83c87d33",
    "metadata": {
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@@ -2480,7 +2480,7 @@
   {
    "cell_type": "code",
    "execution_count": 8,
-   "id": "730d3f1b",
+   "id": "74eaac59",
    "metadata": {
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     "editable": true
@@ -2558,7 +2558,7 @@
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   {
    "cell_type": "markdown",
-   "id": "b74f882c",
+   "id": "aa703354",
    "metadata": {
     "editable": true
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@@ -2568,7 +2568,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "83de40c4",
+   "id": "f8bffca6",
    "metadata": {
     "editable": true
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@@ -2597,7 +2597,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "1353fa72",
+   "id": "109c07d6",
    "metadata": {
     "editable": true
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@@ -2613,7 +2613,7 @@
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   {
    "cell_type": "markdown",
-   "id": "7231e849",
+   "id": "1ea48f22",
    "metadata": {
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@@ -2632,7 +2632,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "caebd625",
+   "id": "212f90ec",
    "metadata": {
     "editable": true
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@@ -2646,7 +2646,7 @@
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   {
    "cell_type": "markdown",
-   "id": "ad52f63e",
+   "id": "a019e7cb",
    "metadata": {
     "editable": true
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@@ -2658,7 +2658,7 @@
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   {
    "cell_type": "markdown",
-   "id": "fdc9cb98",
+   "id": "2ca46c43",
    "metadata": {
     "editable": true
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@@ -2669,7 +2669,7 @@
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   {
    "cell_type": "markdown",
-   "id": "7dcf3e2f",
+   "id": "c61ed9c8",
    "metadata": {
     "editable": true
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@@ -2681,7 +2681,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "accbfe1b",
+   "id": "96d84043",
    "metadata": {
     "editable": true
    },
@@ -2693,7 +2693,7 @@
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   {
    "cell_type": "markdown",
-   "id": "3197f85d",
+   "id": "e53b66df",
    "metadata": {
     "editable": true
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@@ -2709,7 +2709,7 @@
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   {
    "cell_type": "markdown",
-   "id": "c59e25e0",
+   "id": "71d542a3",
    "metadata": {
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@@ -2720,7 +2720,7 @@
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   {
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-   "id": "ef8f7423",
+   "id": "01b18637",
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@@ -2743,7 +2743,7 @@
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   {
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-   "id": "3a299c34",
+   "id": "e35bdcc1",
    "metadata": {
     "editable": true
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@@ -2754,7 +2754,7 @@
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   {
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-   "id": "da2704d8",
+   "id": "15b7ea3c",
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@@ -2766,7 +2766,7 @@
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-   "id": "77f05c54",
+   "id": "a4c5f625",
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@@ -2778,7 +2778,7 @@
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   {
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+   "id": "450007e4",
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@@ -2792,7 +2792,7 @@
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-   "id": "9310dcea",
+   "id": "3bcf81c1",
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@@ -2823,7 +2823,7 @@
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-   "id": "75cc0bec",
+   "id": "f69a019e",
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@@ -2845,7 +2845,7 @@
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+   "id": "95b37da0",
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@@ -2857,7 +2857,7 @@
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+   "id": "241c2335",
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@@ -2870,7 +2870,7 @@
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    "cell_type": "markdown",
-   "id": "6cab3110",
+   "id": "cf794384",
    "metadata": {
     "editable": true
    },
@@ -2882,7 +2882,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "43d81933",
+   "id": "4cd5260a",
    "metadata": {
     "editable": true
    },
@@ -2894,7 +2894,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "e9d139ab",
+   "id": "7361e846",
    "metadata": {
     "editable": true
    },
@@ -2906,7 +2906,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "d9cf88c7",
+   "id": "6a07837b",
    "metadata": {
     "editable": true
    },
diff --git a/doc/src/week37/week37.do.txt b/doc/src/week37/week37.do.txt
index 7a20ff512..39c2d5e8b 100644
--- a/doc/src/week37/week37.do.txt
+++ b/doc/src/week37/week37.do.txt
@@ -339,7 +339,7 @@ p(\bm{\beta}\vert\bm{D})\propto p(\bm{D}\vert\bm{\beta})p(\bm{\beta}).
 \]
 !et
 
-We have a model for $p(\bm{D}\vert\bm{\beta})$ but need one for the _prior_ $p(\bm{\beta}$!   
+We have a model for $p(\bm{D}\vert\bm{\beta})$ but need one for the _prior_ $p(\bm{\beta})$!   
 
 
 !split
@@ -710,10 +710,10 @@ unknown parameter such as the parameters $\bm{\beta}$ from linear regression.
 With the OLS expressions for the parameters $\bm{\beta}$ we found 
 $\mathbb{E}(\bm{\beta}) = \bm{\beta}$, which means that the estimator of the regression parameters is unbiased.
 
-We found also that the variance of the estimate of the $j$-th regression coefficient is
+In the exercises this week we show that the variance of the estimate of the $j$-th regression coefficient is
 $\bm{\sigma}^2 (\bm{\beta}_j ) = \bm{\sigma}^2 [(\mathbf{X}^{T} \mathbf{X})^{-1}]_{jj} $.
 
-This quantity will be used to
+This quantity can be used to
 construct a confidence interval for the estimates.