What Is a Confidence Interval?

Calculation: AP Statistics Students (Two-Sample Mean)

A standardized AP test is used to assess the knowledge of AP Statistics of 200 12th graders at Lynden High School (reported mean=3.05, standard deviation=1)*. A sample of 20 students in a single AP class at the high school are tested (sample mean=2.88, standard deviation=1.1). Compute a 95 percent confidence interval based on this sample's data.

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Hint: Because one sample size is <=30 we are going to use the two-sample CI formula with the t-score ($t^*$) and pooled standard deviation ($S_p$).

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*The data on AP statistics is not accurate for Lynden High School