7.26. A study conducted about an aircraft landing process found that the average ground speed of 150 small airorafts was 125 knots with a standard deviation of 14 knots. The average ground speed of 800 large aircrafts was found to be 132 knots with a standard deviation of 14.5 knots. a. Calculate the pooled standard deviation for the difference between the average ground speed of small and large aircrafts. b. Calculate the standard error for the difference between the average ground speed of small and large aircrafts. c. Calculate the margin of error for a 99% confidence interval for the difference between the average ground speed of small and large airorafts. d. Calculate the 99% confidence interval for the difference between the average ground speed of small and large airorafts. e. Interpret the interval in part 0. Can you determine a difference in average ground speed between small and large aircraft? If yes, which is faster? Confidence Interval for pp 0 The mean of the differences is 1.55 with a standard deviation of 1.64. 0 Construct and interpret a 99% confidence interval for the mean difference in DVD sales between the United States and Europe. t* = ian(0.995. 11) = 3.100 1.64 1.55 i 3.106 - \"12 1.55 i 3.106 - 0.473 1.55 :t 1.470 (0.08. 3.02) Interpretation: We are 99% confident that the average difference in DVD sales between the United States and Europe is between 0.08 an 3.02 million