Concept explainers
Preliminary data analyses indicate that you can reasonably use a t-test to conduct each of the hypothesis tests required in Exercises 9.113–9.118.
9.113 TV Viewing. According to Communications Industry Forecast & Report, published by Veronis Suhler Stevenson, the average person watched 4.55 hours of television per day in 2005. A random sample of 20 people gave the following number of hours of television watched per day for last year.
At the 10% significance level, do the data provide sufficient evidence to conclude that the amount of television watched per day
last year by the average person differed from that in 2005? (Note:
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Introductory Statistics (10th Edition)
- What is meant by the sample space of an experiment?arrow_forward6. A manufacturer advertised the median life of an aircraft spark plug as 800 service hours. The FAA doubted the claim and checked a random sample of logbooks on 50 types of planes using this type of plug. In 12 types of airplanes, the spark plugs lasted more than 800 hours (+), but they lasted fewer hours (–) in the remaining 38 airplane types. Was the advertising claim correct? Make an appropriate hypothesis test at the 5 percent level of significance.arrow_forwardA study investigated survival rates for in-hospital patients who suffered cardiac arrest. Among 60,000 patients who had cardiac arrest during the day, 11,610 survived and were discharged. Among 28,500 patients who suffered cardiac arrest at night, 5400 survived and were discharged. Use a 0.01 significance level to test the claim that survival rates are the same for day and night patients. a) Define the parameters and state null and alternative hypothesis b) Test Statistics c) P-value Approach d) Conclusionarrow_forward
- A marketing research firm wants to determine if a new advertising campaign has an effect on sales. The null hypothesis is that the campaign has no effect on sales, meaning the average sales before and after the campaign are equal. The firm conducts a two-sample t-test and obtains a t-statistic of 2.7 and a degrees of freedom of 20. What is the p-value of the hypothesis test?arrow_forwardThe National Cyber Security Alliance claims that 85% of computer owners believe that they have a antivirus program installed on their computer. If a random sample of 400 scanned computers found that 324 of them (81%) actually had an antivirus program installed, use the sample proportion to test the claim at the 90% (? = 0.10) significance level. Use the hypothesis H0: p = 0.85 and H1: p ≠ 0.85 with a two-tail test: Based on the above Z score – should you REJECT the null hypothesis H0? (A) YES (B) NOarrow_forward* In a certain state, a referendum is being held to determine whether the transportation authority should issue additional highway bonds. A sample of 430 voters is taken in county A, and 235 say that they favor the bond proposal. A sample of 500 voters is taken in county B, and 265 say that they favor the bond issue. Perform a hypothesis test to measure the strength of the evidence that the proportion of voters who favor the proposal is greater in county A than in county B. Use the a=0.02 level of significance. Use P Method and list all 6 steps clearly.arrow_forward
- Consider the random sample of college students. Data on gender and Full or Part-time student course load. Use the data to test for independence between Gender and Full or Part-time status. Use a 5% level of significance. Assume all requirements have been met. What is the tail of the test? Find the P-value. Will the null hypothesis be rejected? Do gender and student status appear to be independent? Full Time Part Time Male 16 8 Female 10 14arrow_forwardFor a one-tailed (upper tail) hypothesis test with a sample size of 26 and a .01 level of significance, the critical value of the test statistic t isarrow_forwardFor a statistics class project, a college student randomly samples 75 men who exercise at a gym regularly and 68 women who exercise at a gym regularly. The college student records the number of minutes each person exercises in a given week. The college student believes that the mean number of minutes per week is lower for men than for women. The college student conducts a hypothesis test at the 5% significance level. What conclusion can you draw from the output? The data provide sufficient evidence to reject the null hypothesis and to conclude that the mean number of minutes exercised per week is lower for men than for women. The data provide sufficient evidence to conclude that there is no difference in the mean number of minutes exercised per week for men and women. The data do not provide sufficient evidence to conclude that the mean number of minutes exercised per week is lower for men than for women. We accept the null hypothesis, and conclude that there is a difference in…arrow_forward
- For a lower tail hypothesis test with a sample size of 13 and a .10 level of significance, the critical value of the test statistic t isarrow_forwardHistorically, the percentage of U.S. residents who support stricter gun control laws has been 55%. A recent Gallup Poll of 2500 people showed 1723 in favor of stricter gun control laws . Assume the poll was given to a random sample of people. QUESTION Test the claim that the proportion of those favoring stricter gun control has changed from 0.55. Perform a hypothesis test, using a significance level of 0.01. What are the hypotheses? Null: p=0.55 Alternate: p=0.55 Null: p=0.55 Alternate: p0.55 Null: p=0.55 Alternate: p ≠ 0.55arrow_forwardOver the past few decades, public health officials have examined the link between weight concerns and teen girls’ smoking. Researchers surveyed a group of 273 randomly selected teen girls living in Massachusetts (between 12 and 15 years old). After four years the girls were surveyed again. Sixty-three said they smoked to stay thin. Is there good evidence that more than thirty percent of the teen girls smoke to stay thin? Solve the following problems using the steps in conducting hypothesis tests.arrow_forward
- College Algebra (MindTap Course List)AlgebraISBN:9781305652231Author:R. David Gustafson, Jeff HughesPublisher:Cengage Learning