AP Statistics (Highschool), Confidence Intervals

Question

For a confidence level of 80% with a sample size of 24, find the critical t value.

t = ______

Answer 1

With this question we want to use a t-table, since a critical t-value is mentioned, which you can look up online. To determine what the t-value is in this table given a 80% confidence level we need to calculate the degrees of freedom which is the number of independent values that can be completely random. This is equal to 23 here since the 24th value in the sample size must be a fixed value.

Given 23 degrees of freedom and an 80% confidence level, the t-table returns a critical value of 1.319

I hope that helps