A researcher compares the effectiveness of two different instructional methods for teaching physiology. A sample of 229 students using Method 1 produces a testing average of 72.9. A sample of 192...

A researcher compares the effectiveness of two different instructional methods for teaching physiology. A sample of 229 students using Method 1 produces a testing average of 72.9. A sample of 192 students using Method 2 produces a testing average of 72. Assume that the population standard deviation for Method 1 is 6.68, while the population standard deviation for Method 2 is 14.51. Determine the 95% confidence interval for the true difference between testing averages for students using Method 1 and students using Method 2. Round your answer to one decimal place.

Lower endpoint =

Upper endpoint =