7.1-11 [128.77, 135.23]. 7.1-11. The heart rates (in beats per minute) of 41 ran-domly selected finishers of the Chicago Marathon, fiveminutes after they completed the race, had sample mean= 132 and sample variance s² = 105. Assuming thatthe heart rates of all finishers of the Chicago Marathonfive minutes after completing the race are normally dis-tributed, obtain a 95% confidence interval for their mean.

Answered: 7.1-11. The heart rates (in beats per…

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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12.A sample of n = 16 scores has a mean of M = 65 and an estimated standard error of 2 points. What is the sample variance? s2 = 64 c. s2 = 16 а. b. s2 = 36 d.s? = 4
3. It has been claimed that over 30 percent of entering college students have blood cholesterol levels of at least 200. Randomly select 20 students in the list in Table 1 to test this hypothesis. What conclusion do the 5 percent level of significance?
An electronic company manufactures electrical resistors with Rave = 40 Q and SD= 2, same unit. What is the probability that the manufactured products will exceed 43 Q? Assume normal distribution. O 17.24% O 82.76% O 93.32% O 6.68%
17. A researcher was interested in comparing the salaries of female and male employees at a particular company. Independent simple random samples of 8 female employees and 15 male employees yielded the following weekly salaries (in dollars). Femalel Male 722 518 495 760 562 904 880 1150 556 520 805 904 500 480 520 1250 970 1005 750 605 743 1640 660 Use a 0.05 significance level to test the claim that the mean salary of female employees is less than the mean salary of male employees. Use the traditional method of hypothesis testing. (Note: x1 = 8705.375, x2 = $817.067, s1 = $ 183.855, s2 = $330.146.) %3D %3D %3D %3D
5.28 Risks and insurance. The idea of insurance is that we all face risks that are unlikely but carry high cost. Think of a fire destroying your home. So we form a group to share the risk: we all pay a small amount, and the insurance policy pays a large amount to those few of us whose homes burn down. An insurance company looks at the records for millions of homeowners and sees that the mean loss from fire in a year is μ = $250 per house and that the standard deviation of the loss is σ = $1000. (The distribution of losses is extremely right-skewed: most people have $0 loss, but a few have large losses.) The company plans to sell fire insurance for $250 plus enough to cover its costs and profit. If the company sells 25,000 policies, what is the approximate probability that the average loss in a year will be greater than $270?
7. With a previous contractor, the mean time to replace a streetlight was 3.2 days. A city councilwoman thinks that the new contractor is not getting the streetlights replaced as quickly. She selects a random sample of 12 streetlight service calls for the new contractor, and obtains the following times to replacement (days). 6.2 7.1 5.4 5.5 7.5 2.6 4.3 2.9 3.7 0.7 5.6 1.7 Using a significance level of 0.01, test the councilwoman's claim. You may assume that all conditions are satisfied.
7. In one state, the mean time served in prison by convicted burglars is 18.7 months. A researcher would like to perform a hypothesis test to determine whether the mean amount of time served by convicted burglars in her hometown is different from 18.7 months. She takes a random sample of 11 such cases from court files in her home town and finds that = 21.4 months and s = 7 months. Use a 5% significance level to perform the test. Assume normally distributed population. Perform critical-value (classical) test. Be sure to identify the null and alternate hypotheses and interpret your results. a) Hypotheses: b) Test statistic: c) Critical-value: d) Hypothesis test conclusion and interpretation:
8.What is the sample variance and the estimated standard error for a sample of n = 9 scores with SS = 72? a. s2= 9 and sM = 3 c. s²= 3 and sM = 3 b. s? = 9 and SM = 1 d. s2 = 3 and sM= 1 %3D
6. In December 2001, 38% of adults with children under the age of 18 reported that their family ate dinner together 7 nights a week. In a recent poll, 403 out of 1122 randomly selected adults with children under the age of 18 reported that their family ate dinner together 7 nights a week. Has the proportion of families with children under the age of 18 who eat dinner together 7 nights a week decreased? Use a 0.05 level of significance.
1. One sample from an independent‐measures study has n = 6 with SS = 400. The other sample has n = 9 and SS = 770. Compute the pooled variance/explanation.
9.15 HPV infections in women. Human papillomavirus (HPV) infection is the most common sexually transmitted infection. Certain types of HPV can cause genital warts in both men and women and cervical cancer in women. The U.S. National Health and Nutrition Examination Survey (NHANES) contacted a representative sample of 1921 women between the ages of 14 and 59 years and asked them to provide a self-collected vaginal swab specimen. Of these specimens, 515 tested positive for HPV, indicating a current HPV infection. a. Give the probability, risk, and odds that a randomly selected American woman between the ages of 14 and 59 years has a current HPV infection. b. The survey broke down the data by age group: Age group (years) 14–19 20-24 25–29 30–39 40-49 50–59 Percent HPV positive 24.5 44.8 27.4 27.5 25.2 19.6 Give the risk and the odds of being HPV positive for women in each age group. Which age group has the highest risk, and has the highest odds, of testing positive for HPV?
Dr. Maddan's eye drops are supposed to cause significant reduction is eye redness. The following table shows the results of a recent study where a random sample of individuals took part in a placebo controlled study. No Reduction in Redness Reduction in Redness Total Eye Drops 120 220 340 No Eye Drops Total 120 140 260 240 360 600 With 5% level of significance, determine if eye redness reduction is dependent upon taking the eye drops. Provide, a. the Chi-square statistic. b. the critical value or the p-value. c. Your decision on whether or not to reject Ho.

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