Crownfashions.com wants to estimate the average time that visitors to its website spend browsing the site.In a random sample of 49 visits this week, average browsing time is 13.6 minutes.Assume you know the population standard deviation is 5.2 minutes.Construct an 80% confidence interval estimate of average browsing time for the population of crownfashion.com visitors this week.Report the upper bound for your interval.
A)15.96
B)18.21
C)16.13
D)15.27
E)14.55

Question

Quizplus · Accepted Answer

The upper bound of the 80% confidence interval is calculated using the formula: mean + (z * (standard deviation/sqrt(n))). With a z-value of 1.28 for 80% confidence, the upper bound is 13.6 + (1.28 * (5.2/sqrt(49))) = 14.55.