Concept explainers
For Exercises 7 through 23, perform each of the following steps.
a. State the hypotheses and identify the claim.
b. Find the critical value(s).
c. Find the test value.
d. Make the decision.
e. Summarize the results.
Use the traditional method of hypothesis testing unless otherwise specified.
17. Medical Operations The director of a medical hospital feels that her surgeons perform fewer operations per year than the national average of 211. She selected a random sample of 15 surgeons and found that the mean number of operations they performed was 208.8. The standard deviation of the sample was 3.8. Is there enough evidence to support the director’s feelings at α = 0.10? Would the null hypothesis be rejected at α = 0.01?
Want to see the full answer?
Check out a sample textbook solutionChapter 8 Solutions
Elementary Statistics: A Step By Step Approach
- The proportion of mango trees on an island that produce only dwarf fruit is p1. The proportion of mango trees on a different island that produce only dwarf fruit is p2. What is the null hypothesis for a test to determine if the proportions are different between the two islands? Select the correct answer below: H0: p1−p2≠0 H0: p1−p2=0 H0: p1−p2>0 H0: p1−p2<0arrow_forwardFollow the steps in testing hypothesis to answer the problem:arrow_forwardA dental assistant is interested in the proportion of patients that need a root canal. Let the proportion of patients that need a root canal be p. If the dental assistant wanted to know if the proportion of patients that need a root canal is more than 20%, what are the null and alternative hypotheses? Select the correct answer below: H0: p=0.20; Ha: p<0.20 H0: p>0.20; Ha: p=0.20 H0: p=0.20; Ha: p>0.20 H0: μ=0.20; Ha: μ>0.20arrow_forward
- State the null and alternative hypotheses to be used in testing the following claims also explain type of test.(a) At most, 20% of next year’s wheat crop will be exported to the Soviet Union.(b) On the average, American homemakers drink 3 cups of coffee per day.(c) The proportion of college graduates in Virginia this year who majored in the social sciences is at least 0.15.(d) The average donation to the American Lung Association is no more than $10.(e) Residents in suburban Richmond commute, on the average, 15 kilometers to their place of employmentarrow_forwardBrown wants to conduct an assessment of where employees live and how employees work. Brown wanted to know if where you lived was related to how you worked. What hypothesis tests can be used in this case?arrow_forwardIf the proportion of the population in City A that is over 65 years old is p1 and the proportion of the population in City B that is over 65 years old is p2, what is the null hypothesis for a test to determine if the proportion of the population that is over 65 years old is greater in City A? Select the correct answer below: H0: p1−p2=0 H0: p1−p2>0 H0: p1−p2<0 H0: p1−p2≠0arrow_forward
- You are working for the South Tahoe Tourist Bureau and are interested in determining if there is a relationship between the casino people frequent and the type of gambling that they do at the casino Table Games Slots Sports Harrah’s 50 60 12 Hard Rock 18 22 6 MontBleu 33 29 20 Harvey’s 41 39 20 a. State the null and alternative hypotheses. b. State which hypothesis test should be used. Calculate the p-Value and state the command you entered in the calculator. c. State the conclusion in the context of the problem.arrow_forwardYou are given the following hypotheses H 0 :p=0.3 H A :p not equal 0.3 We know that the sample size 90. For what sample proportion would the pvalue be equal to 0.1? Assume that all conditions necessary for Inference are satisfied.arrow_forwardAfter running a hypothesis test comparing the number of jelly beans that a sample of children eat over the course of the year with the number of jelly beans children eat in the overall population over the course of the year, I conclude that the sample of children ate significantly more jelly beans than the overall population of children. If the sample of children actually ate the same number of jelly beans as the overall population, my conclusion is an example of _______. a. sampling error b. a Type II error c. a Type I error d. a valid conclusionarrow_forward
- The level of significance for a hypothesis is 0.01. If you compute a p-value of 0.0157 what decision should you make?arrow_forwardAt one school, the average amount of time that tenth-graders spend watching television each week is 15.5 hours. The principal introduces a campaign to encourage the students to watch less television. One year later, the principal wants to perform a hypothesis test to determine whether the average amount of time spent watching television per week has changedarrow_forwardWith a p value of .04 and an ⍺ of .05, should you reject or fail to reject the null hypothesis?"arrow_forward
- MATLAB: An Introduction with ApplicationsStatisticsISBN:9781119256830Author:Amos GilatPublisher:John Wiley & Sons IncProbability and Statistics for Engineering and th...StatisticsISBN:9781305251809Author:Jay L. DevorePublisher:Cengage LearningStatistics for The Behavioral Sciences (MindTap C...StatisticsISBN:9781305504912Author:Frederick J Gravetter, Larry B. WallnauPublisher:Cengage Learning
- Elementary Statistics: Picturing the World (7th E...StatisticsISBN:9780134683416Author:Ron Larson, Betsy FarberPublisher:PEARSONThe Basic Practice of StatisticsStatisticsISBN:9781319042578Author:David S. Moore, William I. Notz, Michael A. FlignerPublisher:W. H. FreemanIntroduction to the Practice of StatisticsStatisticsISBN:9781319013387Author:David S. Moore, George P. McCabe, Bruce A. CraigPublisher:W. H. Freeman