Question

A researcher compares the effectiveness of two different instructional methods for teaching physiology. A sample of 54 students using Method 1 produces a testing average of 51.7. A sample of 90 students using Method 2 produces a testing average of 56.8. Assume that the population standard deviation for Method 1 is 7.35, while the population standard deviation for Method 2 is 16.72. Determine the 80% confidence interval for the true difference between testing averages for students using Method 1 and students using Method 2.

Step 2 of 3:

Calculate the margin of error of a confidence interval for the difference between the two population means. Round your answer to six decimal places.

Answer 1

Solution:

Given:

Confidence level = 0.80

Therefore, = 1-0.80 = 0.20

Using standard normal table,

Marging of error is,

Therefore, 80% confidence interval for the true difference between testing averages for students using Method 1 and students using Method 2:

Done