Exhibit 8-1
In order to estimate the average time spent on the computer terminals per student at a local university, data were collected from a sample of 81 business students over a one-week period. Assume the population standard deviation is 1.2 hours.
-Refer to Exhibit 8-1. If the sample mean is 9 hours, then the 95% confidence interval is approximately
A)7.04 to 110.96 hours
B)7.36 to 10.64 hours
C)7.80 to 10.20 hours
D)8.74 to 9.26 hours

Question

Quizplus · Accepted Answer

The 95% confidence interval is calculated using the formula: sample mean ± (Z * (population standard deviation / √sample size)). With a Z value of 1.96 for 95% confidence, the interval is 9 ± (1.96 * (1.2 / √81)), which is approximately 8.74 to 9.26 hours.

Exhibit 8-1 in Order to Estimate the Average Time Spent on the on the Computer