A researcher compares the effectiveness of two different instructional methods for teaching anatomy. A sample of 293 students using Method 1 produces a testing average of 82.9. A sample of 282 students using Method 2 produces a testing average of 76.5. Assume that the population standard deviation for Method 1 is 7.97, while the population standard deviation for Method 2 is 6.66. Determine the 98% 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. g