Question

A researcher compares the effectiveness of two different instructional methods for teaching anatomy. A sample of 178 178 students using Method 1 produces a testing average of 85.8 85.8 . A sample of 197 197 students using Method 2 produces a testing average of 73.4 73.4 . Assume that the population standard deviation for Method 1 is 5.06 5.06 , while the population standard deviation for Method 2 is 19.39 19.39 . Determine the 95% 95 % confidence interval for the true difference between testing averages for students using Method 1 and students using Method 2.

Step 1 of 2: Find the critical value that should be used in constructing the confidence interval.

Step 2 of 2: Construct the 95% 95 % confidence interval. Round your answers to one decimal place.

Answer 1

The statistical software output for this problem is:

Hence,

Step - 1: Critical value = 1.960

Step - 2: 95% Confidence Interval:

Lower limit = 9.6

Upper limit = 15.2