# Interpreting a Confidence Interval

## Introductions

Introduce yourselves!

Icebreaker: What did you do for Patriot's Day?

## Groupwork

As a WPI admissions intern, you are tasked with estimating the number of admitted students (class of '26) that will be IMGD majors. You sample 400 admitted students to WPI and find that 40 of them are planning on being IMGD majors. The 90% confidence interval for the fraction of incoming students planning on being IMGD majors is 0.10 +- 0.04. Interpret this interval.

1. You are 90% confident that at least 40 of the students will be IMGD majors.

2. You are 90% confident that 24 to 56 of the incoming students will be IMGD majors.

3. There is a 90% chance of selecting a sample that finds that between 6% and 14% of the incoming students will be IMGD majors.

4. You are 90% confident that the true percentage of incoming students that will be IMGD majors is between 24 and 56.

## Hand-in

Have ONE person from each group submit the group's answers:

https://wpi.qualtrics.com/jfe/form/SV_1NzNEVIPwOtmp1A

Make sure to include the names of all group members.

Have fun with confidence!

-- Mark