8. A researcher found that a cigarette smoker smokes on average of 29 cigarettes a day. She thinks the average is actually less than that. She selected a random sample of 12 smokers and found that the mean number of cigarettes they smoked per day was 27. The sample standard deviation was 2.7. At 0.10 level of significance, is there enough evidence to support her claim? Assume that the population is approximately normally distributed. Use the critical value method and tables. ! (a) State the hypotheses and identify the claim. ! (b) Find the critical value. ! (c) Compute the test value. ! (d) Make the decision. ! (e) Summarize the results.