....

5353 4

5:53 Ch 8 Introduction to Hy... Chapter 8 Problems from Gravetter and Wallnau (2014) I. 2. 3. 4. Dashboard Childhood participation in sports, cultural groups, and youth groups appears to be related to improved self-esteem for adolescents (McGee, Williams, Howden-Chapman, Martin, & Kawachi, 2006). In a representative study, a sample of n: 100 adolescents with a history of group participation is given a standardized self-esteem questionnaire. For the general population of adolescents, scores on this questionnaire form a normal distribution with a mean of 50 and a standard deviation of 15. The sample of group participation adolescents had an average of M= 53.8. a. Does this sample provide enough evidence to conclude that self-esteem scores for these adolescents are significantly different from those of general population? Use a two- tailed test with a: .05. Write your results in APA style. b. Compute Cohen's d to measure the size of the difference. In a study examining the effect of alcohol on reaction time, Liguori and Robinson (2001) found that even moderate alcohol consumption significantly slowed response time to an emergency situation in a driving simulation. In a similar study, researchers measured reaction time 30 minutes after participants consumed one 6-ounce glass of wine. Again, they used a standardized driving simulation task for which the regular population averages 400 msec. The distribution of reaction times is approximately normal with 40. Assume that the researcher obtained a sample mean of M= 422 for the n: 25 participants in the study. c. d. Are the data sufficient to conclude that the alcohol has a significant effect on reaction time? Use a two- tailed test with a=.01. Write your results in APA style. Do the data provide evidence that the alcohol significantly increased (slowed) reaction time? Use a one- tailed test with a: .05. Write your results in APA style. There is some evidence indicating that people with visible tattoos are viewed more negatively than people without visible tattoos (Resenhoeft, Villa & Wiseman, 2008). In a similar study, a researcher first obtained overall ratings of attractiveness for a woman with no tattoos shown in a color photograph. On a 7-point scale, the woman received an average rating of 4.9, and the distribution of rating was normal with a standard deviation of 02 0.84. The researcher then modified the photo by adding a tattoo of a butterfly on the woman's left arm. The modified photo was then shown to a sample of n=16 students at a local community college and the students used the same 7-point scale to rate the attractiveness of the woman. The average score for the photo with the tattoo was M= 4.2. e. Do the data indicate a significant difference in rated attractiveness when the woman appeared to have a tattoo? Use a two- tailed test with .05. Write your results in APA style. Montarello and Martens (2005) found that fifth- grade students completed more mathematics problems correctly when simple problems were mixed in with their regular math assignments. To further explore this phenomenon, suppose that a researcher selects a standardized mathematics achievement test that produces a normal distribution of scores with a mean of 100 and a standard deviation of 18. The researcher modifies the test by inserting a set of very easy problems among the standardized questions and gives the modified test to a sample of n= 36 students. If the average test score for the sample is M: 104, is this result sufficient to conclude that inserting the one-tailed test with a: .05. Write your results in APA style. Calendar To Do Notifications Inbox