## Setting Up Hypotheses

This section discusses the logic behind hypothesis testing using concrete examples and explains how to set up null and alternative hypothesis. It explains what Type I and II errors are and how they can occur. Finally, it introduces one-tailed and two-tailed tests and explains which one you should use for testing purposes.

### Introduction

#### Questions

Question 1 out of 3.

Tommy claims that he blindly guessed on a 20-question true/false test, but then he got 16 of the questions correct. Using the binomial calculator, you find out that the probability of getting 16 or more correct out of 20 when $\pi =.5$ is $0.0059$. This probability of $0.0059$ is the probability that...

• he would get $80\%$ correct if he took the test again.
• he would get this score or better if he were just guessing.
• he was guessing blindly on the test.

Question 2 out of 3.

Random assignment ensures groups will be equal on everything except the variable manipulated.

• True
• False

Question 3 out of 3.

The researchers hypothesized that there would be a correlation between how much people studied and their GPAs. The null hypothesis is that the population correlation is equal to

__________