Chapter 7 Hypothesis Testing
Given: We cannot reject H0 at a 5% level of significance (assuming the data follow a normal distribution). A random sample of 50 measurements resulted in a sample mean of 62 with a sample standard deviation 8. It is claimed that the true population mean is at least 64.
(a) Is there sufficient evidence at the 2% level of significance to refute the claim? (b) What is the p-value for the test? (c) What is the smallest value of α for which the claim will be rejected?
A machine in a certain factory must be repaired if it produces more than 12% defectives among the large lot of items it produces in a week. A random sample of 175 items from a week's production contains 45 defectives, and it is decided that the machine must be repaired.
(a) Does the sample evidence support this decision? Use α = 0.02.
(b) Compute the p-value.
A random sample of 78 observations produced the following sums: Σ xi = 22.8, Σ(xi − x̄)² = 2.05.
(a) Test the null hypothesis that μ = 0.45 against the alternative that μ < 0.45 using α = 0.01. Also find the p-value.
(b) Test the null hypothesis that μ = 0.45 against the alternative that μ > 0.45 using α = 0.01. Also find the p-value.
(c) What assumptions did you make for solving (a) and (b)?
Consider the test H0: μ = 35 vs Ha: μ > 35 for a random sample of 18 observations taken from a population that is normally distributed. A sample produced a mean of 40 and a sample standard deviation of 5. Using α = 0.025, would you reject the null hypothesis?
Another random sample of 18 observations produced a sample mean of 40 and a sample standard deviation of 5.