The Sugar Producers Association wants to estimate the mean yearly sugar consumption. A sample of 25 people reveals the mean yearly consumption to be 27 kg with a sample standard deviation of 9 kg. Assume a normal population. For a 99% confidence interval, what is the critical value needed?
A) t = 1.708
B) t = 1.711
C) t = 2.797
D) z = 1.645
E) z = 1.96

Question

Quizplus · Accepted Answer

Since the population standard deviation is unknown and the sample size is less than 30, a t-distribution is used. For a 99% confidence interval with 24 degrees of freedom (n-1 = 25-1), the critical value is t = 2.797.

The Sugar Producers Association Wants to Estimate the Mean Yearly