The paper referenced in Exercise 15.5 described an experiment to determine it restrictive age labeling on video games increased the attractiveness of the game for boys age 12 to 13. In that exercise, the null hypothesis
- a. Calculate the 95% T-K intervals and then use the underscoring procedure described in this section to identify significant differences among the age labels.
- b. Based on your answer to Part (a), write a few sentences commenting on the theory that the more restrictive the age label on a video game, the more attractive the game is to 12- to 13-year-old boys.
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Chapter 15 Solutions
Introduction to Statistics and Data Analysis
- What is an experiment?arrow_forwardA researcher is interested in exploring the relationship between calcium intake and weight loss. Two different groups, each with 29 dieters, are chosen for the study. Group A is required to follow a specific diet and exercise regimen, and also take a 500-mg supplement of calcium each day. Group B is required to follow the same diet and exercise regimen, but with no supplemental calcium. After six months on the program, the members of Group A had lost a mean of 10.4 pounds with a standard deviation of 1.2 pounds. The members of Group B had lost a mean of 10.6 pounds with a standard deviation of 1.9 pounds during the same time period. Assume that the population variances are not the same. Construct a 90% confidence interval to estimate the true difference between the mean amounts of weight lost by dieters who supplement with calcium and those who do not. Let Population 1 be the amount of weight lost by Group A, who took a 500-mg supplement of calcium each day, and let Population 2 be the…arrow_forwardIn a test of the hypothesis that females smile at others more than males do, females and males were videotaped while interacting and the number of smiles emitted by each sex was noted. Using the following information regarding number of smiles in the five-minute interaction, examine whether there are sex differences in the number of smiles. Males Females N1 = 5 N2 = 5 X1 = 7.6 X2 = 15.2 S12 = 17.04 S22 = 8.96 Which is the independent variable and which is the dependent variable? What is your research hypothesis? What is your null hypothesis? Which test should you use (Two Sample Independent t, ANOVA, Chi-square, or correlation )? Calculate the test statistic. interpret whether you have statistically significant results when α = .05. State whether the null hypothesis is rejected. Include critical region. Provide an overall sentence about the…arrow_forward
- A researcher is interested in exploring the relationship between calcium intake and weight loss. Two different groups, each with 21dieters, are chosen for the study. Group A is required to follow a specific diet and exercise regimen, and also take a 500-mg supplement of calcium each day. Group B is required to follow the same diet and exercise regimen, but with no supplemental calcium. After six months on the program, the members of Group A had lost a mean of 12.2 pounds with a standard deviation of 2.5 pounds. The members of Group B had lost a mean of 14.7 pounds with a standard deviation of 2.3 pounds during the same time period. Assume that the population variances are not the same. Construct a 90%90% confidence interval to estimate the true difference between the mean amounts of weight lost by dieters who supplement with calcium and those who do not. Let Population 1 be the amount of weight lost by Group A, who took a 500-mg supplement of calcium each day, and let Population 2 be…arrow_forwardA social psychologist wants to know if people judge a person's attractiveness differently if they appear rich or poor. Two pictures were taken with the same model, one in expensive clothes standing next to a new sports car, and the other in old clothes standing next to an old hatchback car. In an online survey, participants were randomly divided so that they saw one of the two pictures and were asked to rate the model's attractiveness on a scale of 1 to 10. Which statistical test would be best to determine if there is a significant difference between groups? one-sample t-test dependent samples t-test independent samples t-test ANOVAarrow_forwardA social psychologist wants to know if people judge a person's attractiveness differently if they appear rich or poor. Two pictures were taken with the same model, one in expensive clothes standing next to a new sports car, and the other in old clothes standing next to an old hatchback car. In an online survey, participants were randomly divided so that they saw one of the two pictures and were asked to rate the model's attractiveness on a scale of 1 to 10. Which statistical test would be best to determine if there is a significant difference between groups? independent samples t-test was wrong.arrow_forward
- A researcher conducts a study examining the effectiveness of a group exercise program at an assisted living facility for elderly adults. One group of residents is selected to participate in the program, and a second group serves as a control. After 12 weeks, the researcher records a combined score measuring balance and strength for each individual. The data are as follows: Control n = 20 M = 24 SS = 241Exercise n = 30 M = 31 SS = 380 a. Use a two-tailed test with a = 0.1. Conduct the four steps for hypothesis testing and label each step: Step1, Step 2, Step 3, and Step 4.arrow_forwardSiegel (1990) found that elderly people who owned dogs were less likely to pay visits to their doctors after upsetting events than were those who did not own pets. Similarly, consider the following hypothetical data. A sample of elderly dog owners is compared to a similar group (in terms of age and health) who do not own dogs. The researcher records the number of doctor visits during the past year for each person. The data are as follows. Control group:10,8,7,9,13,7,6,12 Dog owners: 7, 4,9,3,7 a. In words and symbols, state the null hypothesis and the alternative hypothesis using a two-tailed test. By hand, compute the degrees of freedom and report the appropriate critical value for a two-tailed test at the α < .05 level. By hand, compute the SS for both groups. By hand, compute the pooled variance for these data. By hand, compute the appropriate test to determine if significant differences occur between these groups. By hand, calculate the appropriate statistical test to…arrow_forwardA manufacturer ran an experiment to compare the wearing qualities of two different types of automobile tires, A and B. In the experiment, a tire of Type A and one of the type B were randomly assigned and mounted on the rear wheels of each of five cars. the cars were then operated for x miles and the amount of tire wear was recorded (higher number represents more wear). Is there sufficient evidence to conclude that there is a difference in the average wear? Use 0.05 level of significance. Tire A 10.6 9.8 12.3 9.7 8.8 Tire B 10.2 9.4 11.8 9.1 8.3arrow_forward
- Researchers have noted a decline in cognitive functioning as people age (Bartus, 1990). However, the results from other research suggest that the antioxidants in foods such as blueberries may reduce and even reverse these age-related declines (Joseph et al., 1999). To examine this phenomenon, suppose that a researcher obtains a sample of n = 16 adults who are between the ages of 65 and 75. The researcher uses a standardized test to measure cognitive performance for each individual. The participants then begin a 2-month program in which they receive daily doses of a blueberry supplement. At the end of the 2-month period, the researcher again measures cognitive performance for each participant. The results show an average increase in performance of Mp = 7.4 with SS = 1215. a. Does this result support the conclusion that the antioxidant supplement has a significant effect on cognitive performance? Use a two-tailed test with a = = .05. (1) Ho: (Select] ( Select ] [ Select ] H: ( Select ] […arrow_forwardResearchers have noted a decline in cognitive functioning as people age (Bartus, 1990). However, the results from other research suggest that the antioxidants in foods such as blueberries may reduce and even reverse these age-related declines (Joseph et al., 1999). To examine this phenomenon, suppose that a researcher obtains a sample of n = 16 adults who are between the ages of 65 and 75. The researcher uses a standardized test to measure cognitive performance for each individual. The participants then begin a 2-month program in which they receive daily doses of a blueberry supplement. At the end of the 2-month period, the researcher again measures cognitive performance for each participant. The results show an average increase in performance of MD = 7.4 with SS = 1215. Does this result support the conclusion that the antioxidant supplement has a significant effect on cognitive performance? Use a two-tailed test with α = .05. Show your computations.arrow_forwardA survey was conducted to investigate the relationship between gender (male and females) and sector of employment (private, government and academia). Using the information provided, does a relationship exist between gender and employment sector at the 5% significance level? Define the null hypothesis and the alternative hypothesis. A. H0: Gender and employment sector are independent vs H1: A relationship exists between gender and employment sector B. H1: Gender and employment sector are independent vs H0: No relationship exists between gender and employment sector C. H1: Gender and employment sector are independent vs H0: Gender is dependent on employment sector D. H0: A relationship exists between gender and employment sector vs H1: No relationship exists between gender and employment sectorarrow_forward
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