Testing Hypotheses. In Exercises 9-24, assume that a simple random sample has been selected and test the given claim. Unless specified by your instructor, use either the P-value method or the critical value method for testing hypotheses. Identify the null and alternative hypotheses, test statistic, P-value (or
19. Years in College lasted below arc the numbers of years it took for a random sample of college students to cam bachelor’s degrees (based on data from the National Center for Education Statistics). Use a 0.01 significance level to test the claim that for all college students, the
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Elementary Statistics
- Testing Hypotheses. In Exercises 13–24, assume that a simple random sample has been selected and test the given claim. Unless specified by your instructor, use either the P-value method or the critical value method for testing hypotheses. Identify the null and alternative hypotheses, test statistic, P-value (or range of P-values), or critical value(s), and state the final conclusion that addresses the original claim. Car Booster Seats The National Highway Traffic Safety Administration conducted crash tests of child booster seats for cars. Listed below are results from those tests, with the measurements given in hic (standard head injury condition units). The safety requirement is that the hic measurement should be less than 1000 hic. Use a 0.01 significance level to test the claim that the sample is from a population with a mean less than 1000 hic. Do the results suggest that all of the child booster seats meet the specified requirement?arrow_forwardDetermining Sample Size. In Exercises 19–22, assume that each sample is a simple random sample obtained from a normally distributed population. Use Table 7-2 on page 338 to find the indicated sample size. IQ of Statistics Professors You want to estimate σ for the population of IQ scores of statistics professors. Find the minimum sample size needed to be 95% confident that the sample standard deviation s is within 1% of σ . Is this sample size practical?arrow_forwardDetermining Sample Size. In Exercises 19–22, assume that each sample is a simple random sample obtained from a normally distributed population. Use Table 7-2 on page 338 to find the indicated sample size. Space Mountain You want to estimate σ for the population of waiting times for the Space Mountain ride in Walt Disney World. You want to be 99% confident that the sample standard deviation is within 1% of σ . Find the minimum sample size. Is this sample size practical?arrow_forward
- Testing Claims About Proportions. In Exercises 7–22, test the given claim. Identify the null hypothesis, alternative hypothesis, test statistic, P-value or critical value(s), then state the conclusion about the null hypothesis, as well as the final conclusion that addresses the original claim. Dreaming in Black and White A study was conducted to determine the proportion of people who dream in black and white instead of color. Among 306 people over the age of 55, 68 dream in black and white, and among 298 people under the age of 25, 13 dream in black and white (based on data from “Do We Dream in Color?” by Eva Murzyn, Consciousness and Cognition , Vol. 17, No. 4). We want to use a 0.01 significance level to test the claim that the proportion of people over 55 who dream in black and white is greater than the proportion of those under 25. a. Test the claim using a hypothesis test. b. Test the claim by constructing an appropriate confidence interval. c. c. An explanation given for the…arrow_forwardUsing the P-value method decide if you should reject the null hypothesis or not. In a sample of 81 adults selected randomly from one town, it is found that 8 of them have been exposed to a particular strain of the flu. At the 0.01 level of significance, you wish to test the proportion of all adults in the town that have been exposed to this strain of the flu is 8%arrow_forwardCritical Value For the survey described in Exercise 1 “Celebrities and the Law,” find the critical value that would be used for constructing a 99% confidence interval estimate of the population proportion.arrow_forward
- Technology. In Exercises 9–12, test the given claim by using the display provided from technology. Use a 0.05 significance level. Identify the null and alternative hypotheses, test statistic, P-value (or range of P-values), or critical value(s), and state the final conclusion that addresses the original claim. Old Faithful Data Set 23 “Old Faithful” in Appendix B includes data from 250 random eruptions of the Old Faithful geyser. The National Park Service makes predictions of times to the next eruption, and the data set includes the errors (minutes) in those predictions. The accompanying Statdisk display results from using the prediction errors (minutes) to test the claim that the mean prediction error is equal to zero. Comment on the accuracy of the predictions. For Exercise 11arrow_forwardPerform a statistical test for the given problem. Follow the steps in hypothesis testing when you present your results. To find out whether a new serum would arrest leukemia, 16 patients, who had all reached an advanced stage of the disease, were selected. Eight patients received the treatment and eight did not. The survival was taken from the time the experiment was conducted. Without Treatment: 1.8, 2.9, 3.3, 3.1, 2.4, 1.5, 1.5, 1.6 With Treatment: 3.9, 4.8, 4.7, 4.9, 4.2, 4.5, 5.5, 4.2arrow_forwardTechnology. In Exercises 9–12, test the given claim by using the display provided from technology. Use a 0.05 significance level. Identify the null and alternative hypotheses, test statistic, P-value (or range of P-values), or critical value(s), and state the final conclusion that addresses the original claim. Body Temperatures Data Set 3 “Body Temperatures” in Appendix B includes 93 body temperatures measured at 12AM on day 1 of a study, and the accompanying XLSTAT display results from using those data to test the claim that the mean body temperature is equal to 98.6°F. Conduct the hypothesis test using these results. For Exercise 10arrow_forward
- Define what a hypothesis is and how it is used in the research process. How are hypotheses tested? What does it mean if a hypothesis is accepted or rejected?arrow_forwardTEST THE SIGNIFICANCE OF THE CORELATION COEFFICENT AT 0.05 LEVEL OF SIGNIFICANCE. (FOLLOW THE 5-STEP PROCEDURE IN HYPOTHESIS TESTING)arrow_forwardTesting Normality For the hypothesis test described in Exercise 2, the sample sizes are n1 = 147 and n2 = 153. When using the F test with these data, is it correct to reason that there is no need to check for normality because n1 > 30 and n2 > 30?arrow_forward
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