Question

A manufacturer of cream filled donuts collected data from its automatic filling process, the amount of cream inserted into the donuts is normally distributed. To make sure that the automatic filling process is on target, quality control inspectors take a sample of 25 donuts. The correct value of t* to construct a 99% confidence interval for the true mean amount of cream filling is ________. Group of answer choices 2.797 1.318 1.711 2.060 2.787

Answer 1

The correct value is t* = 2.797.

Explanation:

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 25 - 1 = 24

99% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 24 degrees of freedom(y-axis) and a two-tailed confidence level of
`1 - (1 - 0.99)/(2) = 0.995`. So we have T = 2.797.