McAllister et al. (2012) compared varsity football and hockey players with varsity athletes from noncontact sports to determine whether exposure to head impacts during one season have an effect on cognitive performance. In the study, tests of new learning performance were significantly poorer for the contact sport athletes compared to the noncontact sport athletes. The following table presents data similar to the results obtained in the study. Noncontact Athletes: 10, 8, 7, 9, 13, 7, 6, 12 Contact Athletes: 7, 4, 9, 3, 7, 6, 10, 2   a. Are the test scores significantly lower for the contact sport athletes than for the noncontact athletes? Use a two-tailed test with =.05 b. What sampling technique was most likely employed by the researcher? justify your answer c. Does exposure to head impacts have an effect on cognitive performance? why or why not

A researcher would like to know if stress has a negative effect on memory performance. One group of participants was exposed to a stress inducing noise and the second group listened to a calming music. Afterwards, both groups were given a memory test. The researcher compared the average memory test scores of two groups. What is the dependent variable in this experiment? Stress inducing noise. O Stress reducing calming music. O Level of stress (i.e., stress inducing noise or calming music) Memory test performance.

Statistics Question

Swedish researchers concluded that viewing and discussing art soothes the soul and helps relieve medical conditions such as high blood pressure and constipation. This conclusion was based on a study in which 15 elderly women gathered once a week to discuss different works of art. The study also included a control group of 15 elderly women who met once a week to discuss their hobbies and interests. At the end of 4 months, the art discussion group was found to have a more positive attitude, to have lower blood pressure, and to use fewer laxatives than the control group.   (a) Why would it be important to determine if the researchers assigned the women participating in the study at random to one of the two groups?   Assigning women at random satisfies the conditions of a single-blind experiment. 2. Assigning women at random is not important for the study and can be neglected.      3.Assigning women at random ensures that the two groups are comparable.     (b) Explain why you think that…

In an early study of the effects of frustration on feelings of hostility, Miller and Bugelski (1948) had a group of boys at a camp rate their attitudes toward two groups (Mexicans and Japanese). The campers then participated in a long, difficult, frustrating testing session that kept them away from their weekly movie. Finally the boys again rated their attitudes towards the minority groups. The scores below represent the number of unfavorable traits attributed to minorities and are similar to those of miller and Bugelski.    Participant   Before          After    A                  5                    6    B                  4                    4    C                  3                    5    D                  3                    4    E                  2                    4    F                  2                     3    G                 1                    3    H                 0                    2   a. Does the intervening unpleasant task alter attitudes toward the two…

Of all sports, football accounts for the highest incidence of concussion in the United States due to the large number of athletes participating and the nature of the sport. While there is general agreement that concussion incidence can be reduced by making rule changes and teaching proper tackling technique, there remains debate as to whether helmet design may also reduce the incidence of concussion. Rowson et al. (2014) report on a retrospective analysis of head impact data collected between 2005 and 2010 from eight collegiate football teams. Concussion rates for players wearing two types of helmets, Riddell VSR4 and Riddell Revolution, were compared. A total of 1,281,444 head impacts were recorded, from which 64 concussions were diagnosed. The relative risk of sustaining a concussion in a Revolution helmet compared with a VSR4 helmet was 46.1%. This study illustrates that differences in the ability to reduce concussion risk exist between helmet models in football. Although helmet…

A study of the differences in cognitive function between normal individuals and patients diagnosed with schizophrenia was published in the American Journal of Psychiatry (Apr. 2010). The total time (in minutes) a subject spent on the Trail Making Test (a standard psychological test) was used as a measure of cognitive function. The researchers theorize that the mean time on the Trail Making Test for schizophrenics will be larger than the corresponding mean for normal subjects. The data for independent random samples of 41 schizophrenics and 49 normal individuals yielded the following results: ***PHOTO   Does the data provide significant evidence, at the  4.6% level, that the population mean time for patients diagnosed with schizophrenia exceeds the population mean time for normal individuals by more than 20 points?

In this same passage, is it explanatory variable or response variable?

An important issue is whether there are racial differences in hypertension among children. We define hypertension as being above the 95th percentile for either systolic blood pressure (SBP) or diastolic blood pressure (DBP) among children of the same age, height, and sex. Since some of the children were observed at multiple visits, a GEE model was run of hypertension on ethnic group. There were three ethnic groups considered: Caucasian, African American, and Hispanic. The results among boys are given in Table 13.54. TABLE 13.54 Relationship between hypertension and ethnic group among 27,009 boys in the Pediatric Task Force Data Variable Regression Coefficient SE Intercept -2.07 0.026 African American 0.049 0.041 Hispanic 0.328 0.059 What is the estimated OR for hypertension comparing Hispanic boys vs. Caucasian boys? (Call this OR1.) What is a 95% CI for this estimate?

In a study about learning styles, researchers used a group of 64 elementary school students who volunteered to be part of the study. The researchers gave each student a pre-test and based upon the results, they divided them into 32 pairs of similarly scoring students. School administrators then randomly assigned one student from each pair to mathematics instruction online while the other student received in-person instruction in a traditional classroom. At the end of the year, all 64 students received a mathematics assessment, measured on a 100-point scale.   The researchers calculated the difference (in person −− online) in the mathematics assessment scores for each pair of students. The 32 differences had a mean of 15 and a standard deviation of 3.9 points.   Construct and interpret a 95% confidence interval for the mean difference (in person −− online) in the mathematics assessment scores for all pairs of students like these who learn math either face-to-face or online.