Question

4. A consumer advocate suspects the true mean weight per bag of a certain brand of potato chips differs from 50 grams, the amount stated on the label. He will take a random sample of 25 bags of chips and conduct a hypothesis test at the 5% level of significance to test his suspicion. Weights per bag are known to follow a normal distribution. What is the probability of making a Type I Error if the null hypothesis is true?

(A) 0.025
(B) 0.050
(C) 0.100
(D) impossible to determine without the value of x ̄

(E) impossible to determine without the value of σ

Answer 1

It is given that the sample follows normal distribution and the population mean assumption is given also the sample size is given as 25.

But to find the P value either for standard normal distribution if population standard deviation is given or for T distribution if population standard deviation is not known we always need the sample mean to find the test statistic and the p value.

So, the correct option is:

(D) impossible to determine without the value of x(bar) .