adding par-financial example to chp 6

Author: CamDavidsonPilon

Chapter2_MorePyMC/MorePyMC.ipynb

@@ -746,6 +746,13 @@
      ],
      "prompt_number": 29
     },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "Later we will see how we use this to make predictions and test the appropriateness of our models."
+     ]
+    },
     {
      "cell_type": "markdown",
      "metadata": {},
@@ -913,7 +920,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "Simiarly, although *not everyone* flips a second time, we can still model the possible realization of second coin-flips:"
+      "Although *not everyone* flips a second time, we can still model the possible realization of second coin-flips:"
      ]
     },
     {
@@ -943,7 +950,7 @@
       "                         fc = first_coin_flips,\n",
       "                         sc = second_coin_flips ):\n",
       "    \n",
-      "    observed = t_a*fc + (1-fc)*sc \n",
+      "    observed = fc*t_a + (1-fc)*sc \n",
       "    return observed.sum()/float(N)"
      ],
      "language": "python",
@@ -955,7 +962,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "The line `t_a*fc + (1-fc)*sc` contains the heart of the Privacy algorithm. Elements in this array are 1 *if and only if* i) the first toss is heads and the student cheated or ii) the first toss is tails, and the second is heads, and are 0 else. Summing this vector and dividing by `float(N)` produces a propotion. "
+      "The line `fc*t_a + (1-fc)*sc` contains the heart of the Privacy algorithm. Elements in this array are 1 *if and only if* i) the first toss is heads and the student cheated or ii) the first toss is tails, and the second is heads, and are 0 else. Summing this vector and dividing by `float(N)` produces a proportion. "
      ]
     },
     {

Chapter3_MCMC/IntroMCMC.ipynb

@@ -1184,8 +1184,12 @@
       "\n",
       "Also important, *bad initial values* are a source of major bugs in PyMC and can hurt convergence.\n",
       "\n",
-      "### priors\n",
-      "### covariance matrices and eliminating parameters"
+      "#### Priors\n",
+      "#### Covariance matrices and eliminating parameters\n",
+      "\n",
+      "### The Folk Theorem of Statistical Computing\n",
+      "\n",
+      ">   *If you are having computational problems, probably your model is wrong.*\n"
      ]
     },
     {