Answer to Question #130815 in Statistics and Probability for Man

Question

A company sells packets of durian crackers that they claim on average, contains at least 20g of durian crackers. They admit that their claim is wrong (and will refund any money), if a sample of 40 durian crackers have a mean less than 19.8g. If the standard deviation is 0.5g, determine the critical value that specifies the rejection region.

Answer 1

critical value

test statistics (z) = (19.8-20)/(0.5/√ 40)

z = -0.2/0.079

z = -2.52

we shall use a significance level of 0.05 which gives us a critical value of -1.65 since this is a one tailed hypothesis.