posted by Maria Elizabeth .
18 workers at a large assembly plant were asked the time it took to commute to work. The data was analyzed in Minitab and the Descriptive Statistics for the data appears below.
Descriptive Statistics: Minutes
Variable N Mean Median TrMean StDev SE Mean
Minutes 18 30.06 29.50 30.06 5.68 1.34
Variable Minimum Maximum Q1 Q3
Minutes 19.00 41.00 26.50 34.00
a) It is known that the standard deviation for all commute times is 6 minutes.
Construct a 98% confidence interval for the average commute time for all workers at the assembly plant. You may use any of the Minitab Output above.
b) Write a complete confidence statement for the interval you calculated in part a.