Concept explainers
The authors of the paper “Flat-footedness Is Not a Disadvantage for Athletic Performance in Children Aged 11 to 15 Years” (Pediatrics [2009]: e386-e392) studied the relationship between y = Arch height and scores on a number of different motor ability tests for 218 children. They reported the following
- a. Interpret the value of the
correlation coefficient between average hopping height and arch height. What does the fact that the correlation coefficient is negative say about the relationship? Do higher arch heights tend to be paired with higher or lower average hopping heights? - b. The title of the paper suggests that having a small value for arch height (flat-footedness) is not a disadvantage when it comes to motor skills. Do the given correlation coefficients support this conclusion? Explain.
Trending nowThis is a popular solution!
Chapter 5 Solutions
Bundle: Introduction to Statistics and Data Analysis, 5th + WebAssign Printed Access Card: Peck/Olsen/Devore. 5th Edition, Single-Term
Additional Math Textbook Solutions
Mathematics for the Trades: A Guided Approach (11th Edition) (What's New in Trade Math)
Elementary Statistics: Picturing the World (7th Edition)
Introductory Statistics
A First Course in Probability (10th Edition)
APPLIED STAT.IN BUS.+ECONOMICS
Elementary & Intermediate Algebra
- Harker and Keltner (2001) examined whether emotional well-being in later life could be predicted from the facial expressions of 141 women in their college yearbook photos. The predictor variable of greatest interest was the “positivity of emotional expression” in the college yearbook photo. They also had these photographs rated on physical attractiveness. They contacted the same women for follow-up psychological assessments at age 52 (and at other ages; data not shown here). Here are the correlations of these two predictors (based on ratings of the yearbook photo) with several of their self-reported social and emotional outcomes at age 52: (scores in screen shot) a. Which of the six correlations above are statistically significant (i) if you test each correlation using α = .05, two-tailed, and (ii) if you set EWα = .05 and use Bonferroni-corrected tests? b. How would you interpret their results? c. Can you make any causal inferences from this study? Give reasons. d. Would it be…arrow_forwardMcAllister 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 one-tailed test with =.05 t-critical= t= b. Compute the value of (percentage of variance accounted for) for these data. r^2= a. 0.123, b. 0.239, c. 0.138, d. 0.264arrow_forwardMcAllister 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 notarrow_forward
- Researchers study the relationship between interpersonal violence and health in colege age women. The researchers report an OR for the use of analgesics among abused versus non abused women (OR 1.45, 95 % , CI 0.97-2.15). Based on this information, you know: In this study women who were abused were 4.5 times as likely to report analgesic use This is a clinically significant result There is no significant difference in analgesic use for abused and non-abused women Abused women are significantly more likely to use analgesicsarrow_forwardA Canadian study measuring depression level in teens (as reported in the Journal of Adolescence, vol. 25, 2002) randomly sampled 112 male teens and 101 female teens, and scored them on a common depression scale (higher score representing more depression). The researchers suspected that the mean depression score for male teens is higher than for female teens, and wanted to check whether data would support this hypothesis. If μ1 and μ2 represent the mean depression score for male teens and female teens respectively, which of the following is an appropriate pair of hypotheses in this case? Check all that apply.arrow_forwardA Canadian study measuring depression level in teens (as reported in the Journal of Adolescence, vol. 25, 2002) randomly sampled 112 male teens and 101 female teens, and scored them on a common depression scale (higher score representing more depression). The researchers suspected that the mean depression score for male teens is higher than for female teens, and wanted to check whether data would support this hypothesis. What conclusion can you draw from the output? The data provide sufficient evidence to reject H0 and to conclude that the mean depression score for male teens is larger than that of female teens. The data provide sufficient evidence to conclude that male and female teens do not differ in mean depression score. The data do not provide sufficient evidence to conclude that the mean depression score of male teens is larger than that of female teens. The data do not provide sufficient evidence to reject H0, so we accept it, and conclude that male and female teens do…arrow_forward
- The participants of this study were classified as "Exercisers" if they exercise for at least 30 minutes, at least 3 times per week, at an aerobic pace. Using an ? = .05 level of significance, is exercising independent of the type of illness? (Be sure to say whether you reject or not reject Ho and why)arrow_forwardOishi and Shigehiro (2010) report that people who move from home to home frequently as children tend to have lower than average levels of well-being as adults. To further examine this relationship, a psychologist obtains a sample of n= 12 adults who each experienced 5 or young more different homes before they were 16 years old These participants were given a standardized well being questionnaire for which the general population has an average score of u = 40. The well-being scores for this sample are as follows: 38, 37,41, 35,42, 40, 33, 33, 36, 38, 32, 39. a. On the basis of this sample, is well-being for frequent movers significantly different from wellbeing in the general population? Use a two-tailed test with a = .05. b. Compute the estimated Cohen's d to measure the size of the difference. c. Write a sentence showing how the outcome of the hypothesis test and the measure of effect size would appear in a research report.arrow_forwardOishi and Shigehiro (2010) report that people who move from home to home frequently as children tend to have lower than average levels of well-being as adults. To further examine this relationship, a psychologist obtains a sample of n=12 young adults who each experienced 5 or more different homes before they were 16 years old. These participants were given a standardized well-being questionnaire for which the general population has an average score of m=40. The well-being scores for this sample are as follows: 38, 37, 41, 35, 42, 40, 33, 33, 36, 38, 32, 39. a. On the basis of this sample, is well-being for frequent movers significantly different from well-being in the general population? Use a two- tailed test with alpha level of .05. b. Compute the estimated Cohen 's d to measure the size of the difference. c. Write a sentence showing how the outcome of the hypothesis test and measure of effect size would appear in a research report.arrow_forward
- A marketing research firm is conducting a study to determine if there is a relationship between an individual's age and the individual's preferred source of news. The research firm asked 1,000 individuals to list their preferred sources for news; newspaper, radio, and television, or the Internet. The accompanying results were obtained. At the 0.01 level of significance, can the marketing research firm conclusion that there is a relationship between the age of the individual and the individual's preferred source for news? Determine the null and alternative hypotheses Calculate the test statistic Calculate the p-value Do you accept or reject the null is there significant evidence? Can the marketing firm conclude that there is a relationship between age and preferred news source?arrow_forwardHarker and Keltner (2001) examined whether emotional well-being in later life could be predicted from the facial expressions of 141 women in their college yearbook photos. The predictor variable of greatest interest was the " positivity of emotional expression" in the college yearbook. They also had these photgraphs rated on physical attractiveness. They contacted the same women for follow-up psychological assessments at age 52 ( and at other ages, data not shown here). Here are the correlations of these two predictors ( based on ratings of the yearbook photo) with several of their self-reported social and emotional outcomes at age 52: In College Photo ---------------------------- At Age 52 Physical Attractiveness Posivity of facialexpression Negative emotionality .04 -.27…arrow_forwardIn a study of a representative group of men, the correlation between height and weight was 0.43. One man in the study was both two SDs above average in height and two SDS above average in weight. His weight will be Ogreater than O less than O about equal to the estimated average weight of all men of his height in the study.arrow_forward
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw HillBig Ideas Math A Bridge To Success Algebra 1: Stu...AlgebraISBN:9781680331141Author:HOUGHTON MIFFLIN HARCOURTPublisher:Houghton Mifflin Harcourt