In Exercises 912, use the sign test for the data consisting of matched pairs.Flight Data

Sign Test for Freshman 15 The table below lists some of the weights from Data Set 4 in Appendix B. Those weights were measured from college students in September and later in April of their freshman year. Assume that we plan to use the sign test to test the claim of no difference between September weights and April weights. What requirements must be satisfied for this test? Is there any requirement that the populations must have a normal distribution or any other specific distribution? In what sense is this sign test a distributionfree test? September weight 67 53 64 74 67 70 55 74 62 57 April weight 66 52 68 77 67 71 60 82 65 58

Identifying Signs For the sign test described in Exercise 1, identify the number of positive signs, the number of negative signs, the number of ties, the sample size n that is used for the sign test, and the value of the test statistic.

Contradicting H 1 An important step in conducting the sign test is to determine whether the sample data contradict the alternative hypothesis H 1 . For the sign test described in Exercise 1, identify the null hypothesis and the alternative hypothesis, and explain how the sample data contradict or do not contradict the alternative hypothesis

Efficiency of the Sign Test Refer to Table 132 in Section 131 and identify the efficiency of the sign test. What does that value tell us about the sign test?

In Exercises 58, assume that matched pairs of data result in the given number of signs when the value of the second variable is subtracted from the corresponding value of the first variable. Use the sign test with a 0.05 significance level to test the null hypothesis of no difference.Positive signs: 13 negative signs: 1 ties: 0 (from a preliminary test of the MicroSort method of gender selection)

In Exercises 58, assume that matched pairs of data result in the given number of signs when the value of the second variable is subtracted from the corresponding value of the first variable. Use the sign test with a 0.05 significance level to test the null hypothesis of no difference. Positive signs: 15 negative signs: 5 ties: 7 (from a class project testing for the difference between reported and measured heights of females)

In Exercises 58, assume that matched pairs of data result in the given number of signs when the value of the second variable is subtracted from the corresponding value of the first variable. Use the sign test with a 0.05 significance level to test the null hypothesis of no difference.Positive signs: 856 negative signs: 151 ties: 57 (from a Pew Research Center poll of adults who were asked if they know what Twitter is)

In Exercises 58, assume that matched pairs of data result in the given number of signs when the value of the second variable is subtracted from the corresponding value of the first variable. Use the sign test with a 0.05 significance level to test the null hypothesis of no difference.Positive signs: 172 negative signs: 439 ties: 0 (from challenges to referee calls in the most recent U.S. Open tennis tournament

In Exercises 912, use the sign test for the data consisting of matched pairs. Oscar Winners Listed below are ages of actresses and actors at the times that they won Oscars. These 10 matched pairs are the first 10 from Data Set 11 in Appendix B. The data are paired according to the years that they won. Use a 0.05 significance level to test the claim that there is no difference between the ages of best actresses and the ages of best actors at the time that the awards were presented. Best Actresses 22 37 28 63 32 26 31 27 27 28 Best Actors 44 41 62 52 41 34 34 52 41 37

In Exercises 912, use the sign test for the data consisting of matched pairs.Oscar Winners Repeat Exercise 9 using all of the 82 pairs of ages in Data Set 11 from Appendix B. For that data set, there are 16 positive signs, 64 negative signs, and 2 ties.

In Exercises 912, use the sign test for the data consisting of matched pairs.Heights of Presidents Refer to Data Set 12 in Appendix B and use the heights of U.S. presidents and their main opponents in the presidential campaigns to test the claim that there is no difference. Use a 0.05 significance level.

In Exercises 912, use the sign test for the data consisting of matched pairs.Flight Data Repeat Example 2 using the following times for American Airlines Flight 19. Taxiout time (min) 15 12 19 18 21 20 13 15 43 18 17 19 Taxiin time (min) 10 10 16 13 9 8 4 3 8 16 9 5

In Exercises 1316, use the sign test for the claim involving nominal data.. Gender Selection The Genetics and IVF Institute conducted a clinical trial of its methods for gender selection. As of this writing, 239 of 291 babies born to parents using the YSORT method were boys. Use a 0.01 significance level to test the claim that the YSORT method has no effect.

In Exercises 1316, use the sign test for the claim involving nominal data.Predicting Sex of Baby A study addressed the issue of whether women have the ability to predict the sex of their babies. Among 104 recruited subjects, 55% correctly guessed the sex of the baby (based on data from Are Women Carrying 'Basketballs' Really Having Boys? Testing Pregnancy Folklore, by Perry, DiPietro, and Constigan, Birth, Vol. 26, No. 3). Use a 0.05 significance level to test the claim that women do not have the ability to predict the sex of their babies.

In Exercises 1316, use the sign test for the claim involving nominal data.Touch Therapy At the age of 9, Emily Rosa tested professional touch therapists to see if they could sense her energy field. She flipped a coin to select either her right hand or her left hand, then she asked the therapists to identify the selected hand by placing their hand just under Emily's hand without seeing it and without touching it. Among 280 trials, the touch therapists were correct 123 times and wrong the other times (based on data in A Close Look at Therapeutic Touch, Journal of the American Medical Association, Vol. 279, No. 13). Use a 0.01 significance level to test the claim that the touch therapists make their selections with a method equivalent to random guesses. Based on the results, does it appear that therapists are effective at identifying the correct hand?

In Exercises 1316, use the sign test for the claim involving nominal data. Football Survey In a USA Today poll, people responded to this question Are today's NFL (football) games too long? Among the respondents with a definitive answer, 242 answered yes and 396 answered no. Use a 0.05 significance level to test the claim that respondents did not have a strong opinion one way or the other. How are the results affected by the additional information that the responses are from Internet users who chose to answer the question posted on the USA Today web site?

Appendix B Data Sets. In Exercises 1720, refer to the indicated data set in Appendix B and use the sign test for the claim about the median of a population Testing for Median Weight of Quarters Refer to Data Set 21 in Appendix B for the weights (g) of randomly selected quarters that were minted after 1964. The quarters are supposed to have a median weight of 5.670 g. Use a 0.01 significance level to test the claim that the median is equal to 5.670 g. Do quarters appear to be minted according to specifications?

Appendix B Data Sets. In Exercises 1720, refer to the indicated data set in Appendix B and use the sign test for the claim about the median of a population Earthquake Magnitudes Refer to Data Set 16 in Appendix B for the earthquake magnitudes. Use a 0.01 significance level to test the claim that the median is equal to 1.00.

Appendix B Data Sets. In Exercises 1720, refer to the indicated data set in Appendix B and use the sign test for the claim about the median of a population Coke Contents Refer to Data Set 19 in Appendix B for the amounts (in oz) in cans of regular Coke. The cans are labeled to indicate that the contents are 12 oz of Coke. Use a 0.05 significance level to test the claim that cans of Coke are filled so that the median amount is 12 oz. If the median is not 12 oz, are consumers being cheated?

Appendix B Data Sets. In Exercises 1720, refer to the indicated data set in Appendix B and use the sign test for the claim about the median of a population Ages of Best Actresses Refer to Data Set 11 in Appendix B for the ages of actresses at the time that they won Oscars in the category of Best Actress. Use a 0.05 significance level to test the claim that the median age of Oscarwinning actresses is equal to 30 years.

Procedures for Handling Ties In the sign test procedure described in this section, we exclude ties (represented by 0 instead of a sign of + or ). A second approach is to treat half of the 0s as positive signs and half as negative signs. (If the number of 0s is odd, exclude one so that they can be divided equally.) With a third approach, in twotailed tests make half of the 0s positive and half negative in onetailed tests make all 0s either positive or negative, whichever supports the null hypothesis. Repeat Example 4 using the second and third approaches to handling ties. Do the different approaches lead to very different results?

Finding Critical Values Table A7 lists critical values for limited choices of . Use Table A1 to add a new column in Table A7 (from n = 1 to n = 8 ) that represents a significance level of 0.03 in one tail or 0.06 in two tails. For any particular n, use p = 0.5 , because the sign test requires the assumption that P ( positive sign ) = P ( negative sign ) = 0.5 . The probability of x or fewer like signs is the sum of the probabilities for values up to and including x.