solve the below mentioned :-
\fA researcher at the Medical College of Virginia conducted a study of 80 randomly selected male soccer players and concluded that frequently "heading" the ball in soccer lowers players' IQs (USA Today, August 14,1995). The soccer players were divided into two groups, based on whether they averaged 10 or more headers per game. Mean IQs were reported in the article, but the sample sizes and standard deviations were not given. Suppose that these values were as given in the accompanying table. n Sample Mean | Sample sd Fewer Than 10 Headers 35 112 10 10 or More Headers 25 103 a. Do these data support the researcher's conclusion? Test the relevant hypotheses using o = 05. b. Can you conclude that heading the ball causes lower IQ?The article "A 'White" Name Found to Help in Job Search" (Associated Press, January 15, 2003) described an experiment to investigate if it helps to have a "white-sounding" first name when looking for a job. Researchers sent 5000 resumes in response to ads that appeared in the Boston Globe and Chicago Tribune. The resumes were identical except that 2500 of them had "white-sounding" first names, such as Brett and Emily, whereas the other 2500 had "black- sounding"names such as Tamika and Rasheed. Resumes of the first type elicited 250 responses and resumes of the second type only 187 responses. Do these data support the theory that the proportion receiving responses is higher for those resumes with "white-sounding first" names?A deficiency of the trace element selenium in the diet can negatively impact growth, immunity. muscle and neuromuscular function, and fertility. The introduction of selenium supplements to dairy cows is justified when pastures have low selenium levels. Authors of the paper "Effects of Short-Term Supplementation with Selenised Yeast on Milk Production and Composition of Lactating Cows" (Australian Journal of Dairy Technology. [2004]: 109-203) supplied the following data on milk selenium concentration (mg/L) for a sample of cows given a selenium supplement (the treatment group) and a control sample given no supplement, both initially and after a 9-day period. held Meupment Inalment 114 10.3 10. 1473 104 12.4 10.3 102 109 132.3 1.7 125 117 8 121.3 a. Use the given data for the treatment group to determine if there is sufficient evidence to conclude that the mean selenium concentration is greater after 9 days of the selenium supplement. b. Are the data for the cows in the control group (no selenium supplement) consistent with the hypothesis of no significant change in mean selenium concentration over the 9-day period? c. Would you use the paired t test to determine if there was a significant difference in the initial mean selenium concentration for the control group and the treatment group? Explain why or why not.The Oregon Department of Health web site provides information on the cost-to-charge ratio (the percentage of billed charges that are actual costs to the hospital). The cost-to-charge ratios for both inpatient and outpatient care in 2002 for a sample of six hospitals in Oregon follow. Inprikent Quipaibni Rail 75 71 71 Oregon hospitals is lower for outpatient care than for inpatient care? Use a significance level of .05.The article "A "White" Name Found to Help in Job Search" (Associated Press, January 15, 2003) described an experiment to investigate if it helps to have a "white-sounding" first name when looking for a job. Researchers sent 5000 resumes in response to ads that appeared in the Boston Globe and Chicago Tribune. The resumes were identical except that 2500 of them had "white-sounding" first names, such as Brett and Emily, whereas the other 2500 had "black- sounding" names such as Tamika and Rasheed. Resumes of the first type elicited 250 responses and resumes of the second type only 187 responses. Do these data support the theory that the proportion receiving responses is higher for those resumes with "white-sounding first" names?In a study of a proposed approach for diabetes prevention, 339 people under the age of 20 who were thought to be at high risk of developing type I diabetes were assigned at random to two groups. One group received twice-daily injections of a low dose of insulin. The other group (the control) did not receive any insulin, but was closely monitored. Summary data (from the article "Diabetes Theory Fails Test," USA Today, June 25, 2001) follow. Number Developing Diabetes Insulin 169 25 Control 170 24 a. Use the given data to construct a 90% confidence interval for the difference in the proportion that develop diabetes for the control group and the insulin group. b. Give an interpretation of the confidence interval and the associated confidence level. c. Based on your interval from Part (a), write a few sentences commenting on the effectiveness of the proposed prevention treatment.In a study to determine if hormone therapy increases risk of venous thrombosis in menopausal women, each person in a sample of 579 women who had been diagnosed with venous thrombosis was classified according to hormone use. Each woman in a sample of 2243 women who had not been diagnosed with venous thrombosis was also classified according to hormone use. Data from the study are given in the accompanying table (Journal of the American Medical Association [2004): 1581-1587). The women in each of the two samples were selected at random from patients at a large HMO in the state of Washington. a. Is there convincing evidence that the proportions falling into each of the hormone use categories is not the same for women who have been diagnosed with venous thrombosis and those who have not? b. To what populations would it be reasonable to generalize the conclusions of Part (a)? Explain. Current Hormone Lise Conjugated Equine None Estrogen Estrogen Venous Thrombosk 372 121 No Venous Thrombosh 1439 515A survey was conducted in the San Francisco Bay area in which each participating individual was classified according to the type of vehicle used most often and city of residence. A subset of the resulting data are given in the accompanying table (The Relationship of Vehicle Type Choice to Personality, Lifestyle, Attitudinal and Demographic Variables, Technical Report UCD-ITS- RR02-08, DaimlerCrysler Corp., 2002). City Yehkk North San Type Conourd Hills Small 231 Compact 142 Large Do the data provide convincing evidence of an association between city of residence and vehicle type? Use a significance level of .05. You may assume that it is reasonable to regard the sample as a random sample of Bay area residents.A story describing a date rape was read by 352 high school students. To investigate the effect of the victim's clothing on subject's judgment of the situation described, the story was accompanied by either a photograph of the victim dressed provocatively, a photo of the victim dressed conservatively, or no picture. Each student was asked whether the situation described in the story was one of rape. Data from the article "The Influence of Victim's Attire on Adolescent Judgments of Date Rape" (Adolescence [1995]: 310-323) are given in the accompanying table. Is there evidence that the proportion who believe that the story described a rape differs for the three different photo groups? Test the relevant hypotheses using o= .01. Response Cornervalle No PLATE Rape 92 Not RapeUsing data from a national survey, the authors of the paper "What Do Happy People Do?" (Social Indicators Research [2008]: 565-571) concluded that there was convincing evidence of an association between amount of time spent watching television and whether or not a person reported that they were happy. They observed that unhappy people tended to watch more television. The authors write: This could lead us to two possible interpretations: 1. Television viewing is a pleasurable enough activity with no lasting benefit, and it pushes aside time spent in other activities-ones that might be less immediately pleasurable, but that would provide long-term benefits in one's condition. In other words, television does cause people to be less happy- 2. Television is a refuge for people who are already unhappy. TV is not judgmental nor difficult, so people with few social skills or resources for other activities can engage in it. Furthermore. chronic unhappiness can be socially and personally debilitating and can interfere with work and most social and personal activities, but even the unhappiest people can click a remote and be passively entertained by a TV. In other words, the causal order is reversed for people who watch television; unhappiness leads to television viewing. Using only data from this study. do you think it is possible to determine which of these two conclusions is correct? If so, which conclusion do you think is correct and why? If not, explain why it is not possible to decide which conclusion is correct based on the study data
