A cereal manufacturer is concerned that the boxes of cereal not be under filled or overfilled.Each box of cereal is supposed to contain 13 ounces of cereal.A random sample of 31 boxes is tested.The average weight is 12.58 ounces and the standard deviation is 0.25 ounces.What is the critical value for testing these hypotheses at $\alpha$ = .001.
A)1.28
B)1.645
C)2.575
D)3.09
E)3.291

Question

Quizplus · Accepted Answer

Since we are testing for a one-tailed hypothesis (under-filled boxes), we need to divide the significance level by 2, giving us a tail probability of 0.001/2 = 0.0005. With 30 degrees of freedom (sample size n-1), the critical value can be found using an F-distribution table or calculator to be approximately 3.291. Therefore, we choose answer E as the best choice.

A Cereal Manufacturer Is Concerned That the Boxes of Cereal α\alphaα

A Cereal Manufacturer Is Concerned That the Boxes of Cereal $\alpha$