Move discussion from index to Instructor Notes (#536)

_extras/guide.md

@@ -3,6 +3,18 @@ layout: page
 title: "Instructor Notes"
 permalink: /guide/
 ---
+
+## About the lesson
+
+Our real goal isn't to teach workshop attendees Python as a programming language,
+but to teach them the basic concepts that all programming depends on.
+We use Python in our lessons because:
+
+1.  It is free and open-source software.
+2.  It is well-documented and runs on all platforms.
+3.  It has a large and constantly growing user-base which includes scientists.
+4.  It is easier for novices to pick up than most other languages.
+
 ## Legend
 
 We are using a dataset with records on inflammation from patients following an

index.md

@@ -5,54 +5,40 @@ root: .
 
 The best way to learn how to program is to do something useful,
 so this introduction to Python is built around a common scientific task:
-data analysis.
+**data analysis**.
 
-Our real goal isn't to teach you Python,
-but to teach you the basic concepts that all programming depends on.
-We use Python in our lessons because:
+### Arthritis Inflammation
+We are studying **inflammation in patients** who have been given a new treatment for arthritis, and
+need to analyze the first dozen data sets of their daily inflammation. The data sets are stored in
+[comma-separated values]({{ page.root }}/reference/#comma-separated-values) (CSV) format:
 
-1.  we have to use *something* for examples;
-2.  it's free, well-documented, and runs almost everywhere;
-3.  it has a large (and growing) user base among scientists; and
-4.  experience shows that it's easier for novices to pick up than most other languages.
-
-But the two most important things are
-to use whatever language your colleagues are using,
-so that you can share your work with them easily,
-and to use that language *well*.
-
-We are studying inflammation in patients who have been given a new treatment for arthritis,
-and need to analyze the first dozen data sets of their daily inflammation.
-The data sets are stored in [comma-separated values]({{ page.root }}/reference/#comma-separated-values) (CSV) format:
-each row holds information for a single patient,
-and the columns represent successive days.
-The first few rows of our first file look like this:
+- each row holds information for a single patient,
+- columns represent successive days.
 
+The first three rows of our first file look like this:
 ~~~
 0,0,1,3,1,2,4,7,8,3,3,3,10,5,7,4,7,7,12,18,6,13,11,11,7,7,4,6,8,8,4,4,5,7,3,4,2,3,0,0
 0,1,2,1,2,1,3,2,2,6,10,11,5,9,4,4,7,16,8,6,18,4,12,5,12,7,11,5,11,3,3,5,4,4,5,5,1,1,0,1
 0,1,1,3,3,2,6,2,5,9,5,7,4,5,4,15,5,11,9,10,19,14,12,17,7,12,11,7,4,2,10,5,4,2,2,3,2,2,1,1
-0,0,2,0,4,2,2,1,6,7,10,7,9,13,8,8,15,10,10,7,17,4,4,7,6,15,6,4,9,11,3,5,6,3,3,4,2,3,2,1
-0,1,1,3,3,1,3,5,2,4,4,7,6,5,3,10,8,10,6,17,9,14,9,7,13,9,12,6,7,7,9,6,3,2,2,4,2,0,1,1
 ~~~
 {: .source}
 
-We want to:
+So, we want to:
 
-*   load that data into memory,
-*   calculate the average inflammation per day across all patients, and
-*   plot the result.
+1. Calculate the average inflammation per day across all patients.
+2. Plot the result to discuss and share with colleagues.
 
 To do all that, we'll have to learn a little bit about programming.
 
 > ## Prerequisites
 >
-> Learners need to understand the concepts of files and directories
-> (including the working directory) and how to start a Python
-> interpreter before tackling this lesson. This lesson references the Jupyter (IPython)
-> Notebook although it can be taught through any Python interpreter.
+> You need to understand the concepts of **files** and **directories** and how to start a Python
+> interpreter before tackling this lesson. This lesson sometimes references Jupyter
+> Notebook although you can use any Python interpreter mentioned in the [Setup](setup/).
+>
 > The commands in this lesson pertain to **Python 3**.
 {: .prereq}
 
 ### Getting Started
-To get started, follow the directions in the "[Setup](setup/)" tab to download data to your computer and follow any installation instructions. 
+To get started, follow the directions on the "[Setup](setup/)" page to download data
+and install a Python interpreter.