In Exercises 5–20, assume that the two samples are independent simple random samples selected from
19. Is Old Faithful Not Quite So Faithful? Listed below are time intervals (min) between eruptions of the Old Faithful geyser. The “recent” times are within the past few years, and the “past” times are from 1995. Does it appear that the
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- Using Normal Approximation. In Exercises 5–8, do the following: If the requirements of np ≥ 5 and nq are both satisfied, estimate the indicated probability by using the normal distribution as an approximation to the binomial distribution; if np ≤ 5 or nq < 5, then state that the normal approximation should not be used. Births of Boys with n= = 8 births and p = 0.512 for a boy, find p (exactly 5 boys).arrow_forwardIn the article “The World's Longest Continued Series of Sea Level Observations” (M. Ekman, Paleogeography, 1988:73–77), the mean annual level of land uplift in Stockholm, Sweden, was estimated to be 4.93 ± 0.23 mm for the years 1774–1884 and to be 3.92 ± 0.19 mm for the years 1885–1984. Estimate the difference in the mean annual uplift between these two time periods, and find the uncertainty in the estimate.arrow_forwardPlease review Section 11.1. Are you an impulse shopper? A survey of 1000 grocery shoppers indicated that 40% of males and 57% of females make an impulse purchase every time they shop. Assume that the survey consisted of 500 males and 500 females. Let group 1 be the males and let group 2 be the females.Ho : pie = pieH1 : pie /= pieCalculate the test statistic: (Round to three decimal places as needed.)Determine the critical value: (Round to three decimal places as needed.)State the Conclusion:arrow_forward
- 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_forwardAn alloy manufacturer is investigating if they can improve the strength of one of their alloysby producing it at a lower temperature. To investigate that, they produce the alloy at twodifferent temperatures (high and low) and then measure the breaking strength of randomsamples of specimens from each. The following table represents the strength of the randomsamples at the higher and lower temperature, in units of 0.001-inch deflection. Temp. Strength (0.001 inch)High 87 64 66 85 76 49 97 73 75 77 69 68 89 27 58 84Low 88 82 81 85 79 80 88 78 77 85 79 76 Do the results support the hypothesis that lowering the production temperature can improve thestrength of the alloy, with 95% confidence? (Hint: Don’t forget investigating variances. Use 98% confidence for that.)arrow_forwardCardiovascular Disease Suppose the incidence rate of myocardial infarction (MI) was 5 per 1000 among 45- to 54-year-old men in 2000. To look at changes in incidence over time, 5000 men in this age group were followed for 1 year starting in 2010. Fifteen new cases of MI were found. Suppose that 25% of patients with Mi in 2000 died within 24 hours. This propartion is called the 24-hour case-fatality rate. Of the 15 new MI cases in the preceding study. 5 died within 24 hours. Test whether the 24-hour case- fatality rate changed from 2000 to 2010.arrow_forward
- A project based on touch therapy is presented at a science fair by a local high school student. In the science fair, practitioners of touch therapy are blindfolded to see if they can detect a "human energy field (HEF)" without touching patients. The student believes that a practitioner with less years of experience predicts more HEF correctly. What can be concluded with an a of 0.01? experience HEF 22 5 21 3 12 2 7 3 9. 5 28 7 15 13 4 4 9. 4 a) Select and compute the appropriate statistic. ---Select--- b) Obtain/compute the appropriate values to make a decision about Ho. Critical Value = X ; Test Statistic = |0.471 Decision: Fail to reject H0 ▼ c) Compute the corresponding effect size(s) and indicate magnitude(s). If not appropriate, input and/or select "na" below... Effect Size = |0.027 ; Magnitude: na d) Make an interpretation based on the results. O Practitioners with more years of experience predict more HEF correctly. Practitioners with less years of experience predict more HEF…arrow_forwarddo question 4, 5 and 6 only The new study claims that the probability of contracting the winter flu among vaccinated high school children is less than 0.5. Assume that p is the population proportion of vaccinated high school children who contract the flu. The appropriate framework to test the new study's claim is H0:p>0.5 vs H1:p<0.5 H0:p=0 vs H1:p≠0 H0:p=0 vs H1:p>0 H0:p=0.5 vs H1:p<0.5 Question 4 The new study takes a random sample of 14 vaccinated high school children. Let x be the number of children in the sample who contract the flu. The p-value for the test can be calculated from a Binomial distribution using P(X≤x). The maximum number of children who can contract the flu to give evidence against the null hypothesis in Question 3 at the 5% level is 1 2 3 5 Question 5 Suppose the actual population proportion of vaccinated high school children who contract the flu is 30%. For a random sample of 14 vaccinated high school children and based on your answer to Question 4,…arrow_forwardDetermine whether the alternative hypothesis is left-tailed, right-tailed, or two-tailed.H0: μ = 44 H1: μ > 44arrow_forward
- , 16. A statistically minded fraternity junior keeps records on how many girls he has to ask before one agrees to be his date for a Saturday football game. His school plays five home games and his five acceptances come on the 3rd, 6th, 4th, 2nd, and 9th girl he asks. Assume that the probability, e, that any girl he asks will accept his invitation is constant from girl to girl. Mind ML estimate of e.arrow_forwardDetermine whether the alternative hypothesis is left-tailed, right-tailed, or two-tailed. H0: μ = 44 H1: μ > 44arrow_forwardAn operator handles adjustments for a group of 8 machines. Adjustment time is exponentially distributed and has a mean of 12 minutes per machine. The machines operate for an average of 85 minutes between adjustments. While running, each machine can turn out 55 pieces per hour. Now find: a. The average number of machines waiting for adjustment. b. The average number of machines being serviced. c. Average downtime. d. The probability that a machine will have to wait for an adjustment.arrow_forward
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