Question

Travelers pay taxes for flying, car rentals, and hotels. The following data represent the total travel tax for a 3-day business trip in eight randomly selected cities.

67.81	78.69	68.99	84.36
80.24	86.14	101.27	99.29

Use Minitab Express to construct the following confidence intervals.  Report your answers rounded to three decimal places, where applicable.

a) We are 90% confident that the mean travel tax for a 3-day business trip to an American city is between $ _____ and $_____

b) We are 90% confident that the standard deviation travel tax for a 3-day business trip to an American city is between $_____ and $_____

Answer 1

from minitab: stat -basic stat -1 sample t - selecting data and setting confidence interval 90%:

below is the output":

Variable N   Mean StDev SE Mean      90% CI
x         8 83.35 12.32     4.36 (75.09, 91.60)

a)

We are 90% confident that the mean travel tax for a 3-day business trip to an American city is between

$ 75.09 and $ 91.60

b

)from minitab: stat -basic stat -1 sample variance - selecting data and setting confidence interval 90%:

90% Confidence Intervals

                         CI for      CI for
Variable Method         StDev      Variance
x         Chi-Square (8.7, 22.1) (76, 491)
          Bonett      (8.7, 22.0) (76, 484)

We are 90% confident that the standard deviation travel tax for a 3-day business trip to an American city is between $ 8.7 and $ 22.1