CHAPTER 12 Cumulative Review Exercises 639 3. Normal Quantile Plot The accompanying normal quantile plot was obtained from the longevity times of presidents. What does this graph tell us? 4. Confidence Interval Use the longevity times of presidents and construct a 95% confidence interval estimate of the population mean. Write a brief statement that interprets the confidence interval. 5. ANOVA The XLSTAT display below results from using the one-way analysis of variance test with the three samples. a. What is the null hypothesis? b. Assuming a 0.05 significance level, what conclusion is indicated by the displayed results? 6. Quarters Assume that weights of quarters minted after 1964 are normally distributed with a mean of 5.670 g and a standard deviation of 0.062 g (based on U.S. Mint specifications). a. Find the probability that a randomly selected quarter weighs between 5.600 g and 5.700 g. b. If 25 quarters are randomly selected, find the probability that their mean weight is greater than 5.675 g. c. Find the probability that when eight quarters are randomly selected, they all weigh less than 5.670 g. d. If a vending machine is designed to accept quarters with weights above the 10th percentile P10, find the weight separating acceptable quarters from those that are not acceptable. 7. Concussions The following table summarizes results from a study of concussions in children (based on data from “Association Between Early Participation in Physical Activity Following Acute Concussion and Persistent Postconcussive Symptoms in Children and Adolescents,” by Grool et al., Journal of the American Medical Association, Vol. 216, No. 23). Use a 0.05 significance level and determine whether physical activity within 7 days after an acute concussion appears to have an effect on symptoms 28 days after a concussion. Symptoms 28 days after concussion? Yes No Physical activity within 7 days after acute concussion? Yes 413 1264 No 320 416
RkJQdWJsaXNoZXIy NjM5ODQ=