Chapter 2 (2.5-2.7)

Question 1

What does the “$” character allow you to do?

Answer 1

Create a new character.

Question 2

True or false: when you create a new object, the name should be written in lowercase letters.

Answer 2

True

Question 3

What does an average causal effect estimate?

Answer 3

The average change in Y caused by a change in X.

Question 4

What’s the best way of ensuring that the treatment group and the control group are comparable?

Answer 4

Running a randomized experiment.

Question 5

True or false: if the outcome variable is binary, the difference-in-means estimator is measured in percentage points.

Answer 5

True

Question 6

What are percentage points?

Answer 6

A unit of measurement for the arithmetic difference between two percentages.

Question 7

What’s the formula for the difference-in-means estimator?

Answer 7

Difference-in-means estimator = average outcome for the treatment group - average outcome for the control group

Question 8

What three arguments does the “ifelse()” function require?

Answer 8

1. logical test (using “==”)
2. a return value if the logical test is true
3. a return value if the logical test is false