# Level of Significance Confidence

A flour manufacturer packs flour into paper bags, each of which is supposed to hold 10 pounds, or 160 ounces. Some customers have complained that the bags hold only 9.5 pounds, or 152 ounces. A test is conducted to determine whether the complaint is warranted. The weight of each bag is normally distributed with a Population Standard Deviation of 5 ounces. A sample of 16 bags yields a mean weight of 156 ounces. Shall we reject the null hypothesis of Mean Weight is exactly equal to 160 ounces with a level of significance of .05? Set up the Hypothesis test in "standard form" and then carry out the test.

© SolutionLibrary Inc. solutionlibary.com 9836dcf9d7 https://solutionlibrary.com/statistics/hypothesis-testing/level-of-significance-confidence-3g4#### Solution Preview

...QRT(N)=5/ SQRT(16)=1.25

For a confidence interval we use: M - z*s < m < M + z*s

The value of z for the 95% confidence interval is the number of standard deviations one must go from the mean (in both directions) to contain 0.95 of the weights. Please refer to attachment below.

It turns out that one must go 1.96 ...