A researcher compares the effectiveness of two different instructional methods for teaching physiology. A sample of 181 students using Method 1 produces a testing average of 57.5. A sample of 227 students using Method 2 produces a testing average of 65. Assume the standard deviation is known to be 14.26 for Method 1 and 7.48 for Method 2. Determine the 98% 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.

If your score on your next statistics test is converted to a z score, which of these z scores would you prefer: minus2.00, minus1.00, 0, 1.00, 2.00? why? a. the z score of 2.00 is most preferable because it is 2.00 standard deviations above the mean and would correspond to the highest of the five different possible test scores. b. the z score of 0 is most preferable because it corresponds to a test score equal to the mean. c. the z score of minus2.00 is most preferable because it is 2.00 standard deviations below the mean and would correspond to the highest of the five different possible test scores. d. the z score of minus1.00 is most preferable because it is 1.00 standard deviation below the mean and would correspond to an above average