In Exercises 5–20, assume that the two samples are independent simple random samples selected from
15. Are Quarters Now Lighter? Weights of quarters are carefully considered in the design of the vending machines that we have all come to know and love. Data Set 29 “Coin Weights” in Appendix B includes weights of a sample of pre-1964 quarters (n = 40,
a. Use a 0.05 significance level to test the claim that pre-1964 quarters have a
b. Construct a confidence interval appropriate for the hypothesis test in part (a).
c. Do post-1964 quarters appear to weigh less than before 1964? If so, why aren’t vending machines affected very much by the difference?
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Chapter 9 Solutions
Essentials of Statistics, Books a la Carte Edition (6th Edition)
- 10 – 11. Margaret, an archeologist, is conducting a test to determine if there is a positive linear relationship between the total height of a dinosaur and its leg length. Her random sample of 15 dinosaur total heights (in feet) and leg lengths (in feet) produced the results shown in the following TI calculator screen. Use the TI calculations in the screen shot to help you answer questions: 10 & 11. LinReg y=a+bx a=28.67845743 b=5.639892354 r=559696513 r=.7481286741 10. What would you predict for a dinosaur's total height (to 2 decimal places) in feet, if the leg length is 5.8 feet? a) 61.39 feet b) 28.68 feet c) 114.99 feet d) 61.33 feet e) 74.81 feet 11. What percent of variation in the dinosaur's total height can be accounted for by the variation in the dinosaur's leg length? a) 28.68% b) 5.64%% c) 55.97% d) 74.81% e) none of thesearrow_forwardpls. answer using 7 steps:-Parameter of interest-Null hypothesisAlternative hypothesis -Test statistic -Reject H0 if: -Computations: -Conclusionarrow_forwardA sociologist wants to determine if the life expectancy of people in Africa is less than the life expectancy of people in Asia. The data obtained is shown in the table below. Africa Asia = 63.3 yr. 1 X,=65.2 yr. 2 o, = 9.1 yr. = 7.3 yr. n1 = 120 = 150arrow_forward
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- Health care workers who use latex gloves with glove powder on a daily basis are particularly susceptible to developing a latex allergy. Each in a sample of 44 hospital employees who were diagnosed with a latex allergy based on a skin-prick test reported on their exposure to latex gloves. Summary statistics for the number of latex gloves used per week are x= 19.4 and s = 11.7. Complete parts (a) - (d). a. Give a point estimate for the average number of latex gloves used per week by all health care workers with a latex allergy. b. Form a 95% confidence interval for the average number of latex gloves used per week by all health care workers with a latex allergy. (Use integers or decimals for any numbers in the expression. Round to two decimal places as needed.) c. Give a practical interpretation of the interval, part (b). O A. One can be 95% confident that latex gloves cause allergies for all who use a number of gloves contained in the interval. O B. One can be 95% confident that the…arrow_forwardHealth care workers who use latex gloves with glove powder on a daily basis are particularly susceptible to developing a latex allergy. Each in a sample of 47 hospital employees who were diagnosed with a latex allergy based on a skin-prick test reported on their exposure to latex gloves. Summary statistics for the number of latex gloves used per week are x = 19.3 and s = 12.3. Complete parts (a) - (d). a. Give a point estimate for the average number of latex gloves used per week by all health care workers with a latex allergy. b. Form a 95% confidence interval for the average number of latex gloves used per week by all health care workers with a latex allergy. (Use integers or decimals for any numbers in the expression. Round to two decimal places as needed.) с. Gi a practical interpretation of the interval, part (b). A. One can be 95% confident that latex gloves cause allergies for all who use a number of gloves contained in the interval. B. One can be 95% confident that the average…arrow_forwardPlease solve part d and e only. The body mass index (BMI) of a person is defined to be the person’s body mass divided by the square of the person’s height. The article “Influences of Parameter Uncertainties within the ICRP 66 Respiratory Tract Model: Particle Deposition” (W. Bolch, E. Farfan, et al., Health Physics, 2001:378–394) states that body mass index (in kg/m2) in men aged 25–34 is lognormally distributed with parameters μ = 3.215 and σ = 0.157. a.Find the mean and standard deviation BMI for men aged 25–34. b.Find the standard deviation of BMI for men aged 25–34. c.Find the median BMI for men aged 25–34. d.What proportion of men aged 25–34 have a BMI less than 20? e.Find the 80th percentile of BMI for men aged 25–34.arrow_forward
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