Correct operator and estimated timing (#455)

03-index-slice-subset.md: Changed `=` to `==`. in Objectives.
index.md: Changed time estimate in introduction.

Fixes #454
Fixes #456

Author: snownontrace

_episodes/03-index-slice-subset.md

@@ -13,7 +13,7 @@ objectives:
     - "Reassign values within subsets of a DataFrame."
     - "Create a copy of a DataFrame."
     - "Query / select a subset of data using a set of criteria using the following operators:
-       `=`, `!=`, `>`, `<`, `>=`, `<=`."
+       `==`, `!=`, `>`, `<`, `>=`, `<=`."
     - "Locate subsets of data using masks."
     - "Describe BOOLEAN objects in Python and manipulate data using BOOLEANs."
 keypoints:

index.md

@@ -5,7 +5,7 @@ root: .
 
 Python is a general purpose programming language that is useful for writing scripts to work effectively and reproducibly with data.
 
-This is an introduction to Python designed for participants with no programming experience. These lessons can be taught in a day (~ 6 hours). They start with some basic information about Python syntax, the Jupyter notebook interface, and move through how to import CSV files, using the pandas package to work with data frames, how to calculate summary information from a data frame, and a brief introduction to plotting. The last lesson demonstrates how to work with databases directly from Python.
+This is an introduction to Python designed for participants with no programming experience. These lessons can be taught in one and a half days (~ 10 hours). They start with some basic information about Python syntax, the Jupyter notebook interface, and move through how to import CSV files, using the pandas package to work with data frames, how to calculate summary information from a data frame, and a brief introduction to plotting. The last lesson demonstrates how to work with databases directly from Python.
 
 > ## Getting Started
 >