A sample of twenty boxes of breakfast cereal delivers a mean weight of 14.9 ounces with a sample standard deviation of 0.3 ounces.Since the label weight of these boxes is 15 ounces,the quality assurance department wants to determine if there is a true weight problem,so they determine the confidence interval at 95% confidence to be ________.
A)14.77 - 15.03 ounces
B)14.70 - 15.10 ounces
C)14.87 - 14.93 ounces
D)14.6 - 15.2 ounces

Question

Quizplus · Accepted Answer

The 95% confidence interval for the mean weight of the cereal boxes, calculated using the sample mean and sample standard deviation, falls within the range of 14.77 - 15.03 ounces. This interval is based on the standard error of the mean and the critical value from the t-distribution (since the population standard deviation is unknown and the sample size is relatively small), which together provide a range that is expected to contain the true population mean 95% of the time.

A Sample of Twenty Boxes of Breakfast Cereal Delivers a Mean