QUESTION TWO a A Mercedes Benz mechanic, in determining whether to purchase a device of design A or design B, checks the times for completing a certain task on each device. Eight operators were used in the testing, with each operator using both device A and B in a randomized order. The times in seconds) required to complete the task are given in the following tables. B Operator A 1 32 2. 40 3 42 4 26 5 35 6 29 7 45 8 22 aaNION 30 39 42 23 36 27 41 21 a) At alpha level equal to 0.05; test to see if there is a significant difference between mean completion times. (5 Marks) b) Determine the 95% level of confidence interval for the difference between A and B. (5 Marks) .​