A hair salon in Cambridge, Massachusetts, reports that on seven randomly selected weekdays, the number of customers who visited
the salon were 41, 64, 43, 28, 54, 44, and 56. It can be assumed that weekday customer visits follow a normal distribution. (You may
find it useful to reference the $t$ table.)
pictureClick here for the Excel Data File
a. Construct the 90% confidence interval for the average number of customers who visit the salon on weekdays. (Round final answers
to 2 decimal places.)
Confidence interval
39.09 to
55.19
b. Construct the 99% confidence interval for the average number of customers who visit the salon on weekdays. (Round final answers
to 2 decimal places.)
Confidence interval
31.78 to
62.50
c. What happens to the width of the interval as the confidence level increases?
As the confidence level increases, the interval becomes wider and less precise.
As the confidence level increases, the interval becomes narrower and less precise.
