A popular restaurant takes a random sample n = 25 customers and records how long each occupied a table. They found a sample mean of 1.2 hours and a sample standard deviation of 0.3 hour. Find the 95 percent confidence interval for the mean.
A) 1.2 ± .118
B) 1.2 ± .124
C) 1.2 ± .588
D) 1.2 ± .609

Question

Quizplus · Accepted Answer

The 95% confidence interval is calculated using the formula: mean ± (t-value * (s/√n)). With n=25, the t-value for 24 degrees of freedom is approximately 2.064. Thus, the interval is 1.2 ± (2.064 * (0.3/√25)) = 1.2 ± 0.124.

A Popular Restaurant Takes a Random Sample N = 25