Active Learning Lecture Slides For use with Classroom Response Systems Statistical Inference: Significance Tests about Hypotheses

Copyright © 2013 Pearson Education, Inc. 9.1 Does a p-value equal to 0.41 show strong evidence OR not show strong evidence against the null hypothesis? a) It does show strong statistically significant evidence against the null hypothesis. b) It does not show strong statistically significant evidence against the null hypothesis. c) It is not possible to determine.

Copyright © 2013 Pearson Education, Inc. 9.2 Does a p-value equal to 0.01 show strong evidence OR not show strong evidence against the null hypothesis? a)It does show strong statistically significant evidence against the null hypothesis. b)It does not show strong statistically significant evidence against the null hypothesis. c)It is not possible to determine.

Copyright © 2013 Pearson Education, Inc. 9.3 Determine if the following statement is a null hypothesis or an alternative hypothesis. “The average amount of time that all Americans spend exercising is 15 minutes a day.” a) b)

Copyright © 2013 Pearson Education, Inc. 9.4 Determine if the following statement is a null hypothesis or an alternative hypothesis. “The population proportion of people that are vegetarian is greater than 0.20.” a) b)

Copyright © 2013 Pearson Education, Inc. 9.5 Planned Parenthood wanted to see if the majority of Texas college students would support allowing those under the age of 18 to have access to birth control pills without their parent’s permission. What would be the null and alternative hypothesis of their study? a) b) c) d) e)

Copyright © 2013 Pearson Education, Inc. 9.6 Suppose that the test statistic equals 1.78, what is the p-value for the hypothesis ? a) b) c) d) e)

Copyright © 2013 Pearson Education, Inc. 9.7 Suppose that the test statistic equals -2.39, what is the p-value for the following hypothesis? a) b) c) d) e) None of the above

Copyright © 2013 Pearson Education, Inc. 9.8 Can consumers determine the difference between Oreos and generic brand Oreo-like cookies? One hundred people are blindfolded and asked to try each kind of cookie and determine which is the Oreo. What are the null and alternative hypothesis to determine if the name brand was identified more often than can be attributed to guessing? a) b) c) d)

Copyright © 2013 Pearson Education, Inc. 9.9 Can consumers determine the difference between Oreos and generic brand Oreo-like cookies? One hundred people are blindfolded and asked to try each kind of cookie and determine which is the Oreo. If 56 people identified the Oreo cookies correctly, was the name brand identified more often than can be attributed to guessing? Compute the test statistic. a) 1.20 b) c) 0.89 d) e) None of the above

Copyright © 2013 Pearson Education, Inc Do the majority of Americans believe that that the penalty for an illegal gun sale should be stricter than the penalty for an illegal drug sale? In 2006, the GSS asked 1,321 respondents this question and 723 said “yes” illegal gun sales should be stricter. What is the conclusion for ? a) We do not have statistically significant evidence that the proportion of Americans that believe that illegal gun sales should be stricter than illegal drug sales is greater than 0.5. b) We have strong statistically significant evidence that the proportion of Americans that believe that illegal gun sales should be stricter than illegal drug sales is greater than 0.5.

Copyright © 2013 Pearson Education, Inc Suppose that you are interested in determining how many days Americans spend on vacation. Your friend thinks that it is 7 days while you think that it is higher than that. You take a simple random sample of 20 people. The sample mean is 8.2 and the standard deviation is 2.4. Find the test statistic. a) 2.57 b) 1.96 c) d) 2.24 e) -2.57

Copyright © 2013 Pearson Education, Inc An environmentalist is interested in studying the amount of dissolved oxygen in a fresh water lake. He is interested in finding if the average dissolved oxygen is significantly different from 8 mg/L. If he finds a p- value equal to 0.034, what can be said about a 95% confidence interval for the population mean? a) A 95% confidence interval would contain 8. b) A 95% confidence interval would not contain 8. c) A 95% confidence interval would contain d) A 95% confidence interval would contain 0. e) It cannot be determined.

Copyright © 2013 Pearson Education, Inc An environmentalist is interested in studying the amount of dissolved oxygen in a fresh water lake. He is interested in finding if the average dissolved oxygen is significantly different from 8 mg/L. If he finds a p-value equal to 0.034, what conclusion can be made? a) We do not have statistically significant evidence that the population mean is different from 8mg/L. b) We do have statistically significant evidence that the population mean dissolved oxygen is different from 8mg/L. c) We do not have statistically significant evidence that the sample mean dissolved oxygen is different from 8mg/L. d) We do have statistically significant evidence that the sample mean dissolved oxygen is different from 8mg/L.

Copyright © 2013 Pearson Education, Inc True or False: If you take a random sample and conduct a significance test there is a 0% chance of making the wrong conclusion. a) True b) False

Copyright © 2013 Pearson Education, Inc An environmentalist is interested in studying the amount of dissolved oxygen in a fresh water lake. He is interested in finding if the average dissolved oxygen is significantly different from 8 mg/L. If he finds a p-value equal to 0.034, for alpha = 0.05 what kind of error could he make? a) Type I b) Type II c) No error can be made

Copyright © 2013 Pearson Education, Inc A bone marrow test is used to diagnose leukemia. A doctor looks at the sample taken from the bone marrow and determines if the person has leukemia. Suppose that the null hypothesis is that there is no disease. What would be a Type I error? a) Stating that the patient has leukemia when they do indeed have leukemia. b) Stating that the patient has leukemia when they do not indeed have leukemia. c) Stating that the patient does not have leukemia when they do indeed have leukemia. d) Stating that the patient does not have leukemia when they do not indeed have leukemia.

Copyright © 2013 Pearson Education, Inc Suppose that a manufacturer of optical fiber is interested in determining if the average strength of a fiber is more than 800kpsi. Describe the Type II error. a) Stating that the fiber was stronger on average than 800kpsi when in reality it was not. b) Stating that the fiber was stronger on average than 800kpsi when in reality it was stronger than 800. c) Stating that there was no statistically significant evidence that the fiber was stronger on average then 800kpsi when in reality it was stronger. d) Stating that there was no statistically significant evidence that the fiber was stronger on average than 800 kpsi when in reality it was not stronger.

Copyright © 2013 Pearson Education, Inc The p-value is… a) the probability that the null hypothesis is true. b) the probability that the null hypothesis is false. c) the probability that the test statistic had the observed result or more extreme if the null hypothesis were true. d) the probability that the test statistic had the observed result or more extreme if the alternative hypothesis was true.