wo men, A and B, who usually commute to work together decide toconduct an experiment to see whether one route is faster than theother. The men feel that their driving habits are approximately thesame, so each morning for two weeks one driver is assigned to routeI and the other to route II. The times, recorded to the nearestminute, are shown in the following table. Using this data, find the98%98%confidence interval for the true mean difference between theaverage travel time for route I and the average travel time forroute II.
Let d=(route I travel time)?(route II travel time)d=(route Itravel time)?(route II travel time). Assume that the populations oftravel times are normally distributed for both routes.
| Day | M | Tu | W | Th | F | M | Tu | W | Th | F |
|---|
| Route I | 32 | 25 | 27 | 32 | 28 | 31 | 32 | 31 | 28 | 32 |
|---|
| Route II | 31 | 23 | 26 | 27 | 25 | 33 | 31 | 27 | 27 | 33 |
|---|
Step 1 of 4: Find the mean of the paired differences, d??. Roundyour answer to one decimal place.
Step 2 of 4: Find the critical value that should be used inconstructing the confidence interval. Round your answer to threedecimal places.
Step 3 of 4: Find the standard deviation of the paireddifferences to be used in constructing the confidence interval.Round your answer to one decimal place.
Step 4 of 4: Construct the 98% confidence interval. Round youranswers to one decimal place.
....lower endpoint...upper endpoint
