A researcher compares the effectiveness of two different instructional methods for teaching physiology. A sample of 78 students using Method 1 produces a testing average of 89.5. A sample of 117 students using Method 2 produces a testing average of 55.9. Assume that the population standard deviation for Method 1 is 16.82, while the population standard deviation for Method 2 is 8. Determine the 99% confidence interval for the true difference between testing averages for students using Method 1 and students using Method 2. Find the point estimate for the true difference between the population means.