Concept explainers
The authors of the paper “Age and Violent Content Labels Make Video Games Forbidden Fruits for Youth” (Pediatrics [2009]: 870–876) carried out an experiment to determine if restrictive labels on video games actually increased the attractiveness of the game for young game players. Participants read a description of a new video game and were asked how much they wanted to play the game. The description also included an age rating. Some participants read the description with an age restrictive label of 7 +, indicating that the game was not appropriate for children under the age of 7. Others read the same description, but with an age restrictive label of 12+, 16+, or 18 +.
The data on the following page for 12- to 13-year-old boys are consistent with summary statistics given in the paper. (The sample sizes in the actual experiment were larger.) For purposes of this exercise, you can assume that the boys were assigned at random to one of the four age label treatments (7+, 12+, 16 +, and 18 + ). Data shown are the boys’ ratings of how much they wanted to play the game on a scale of 1 to 10.
Do the data provide convincing evidence that the means of the ratings associated with the game descriptions by 12- to 13-year-old boys are not the same for all four restrictive rating labels? Test the appropriate hypotheses using a significance level of 0.05. (Hint: See Example 15.4.)
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Chapter 15 Solutions
Introduction To Statistics And Data Analysis
- A random sample of Engineering and Architecture students of a university were interviewed to determine if there is an association between study habits and academic performance. The results were tabulated below. Students Favourable Neutral Unfavourable Engineering 80 60 70 Architecture 100 50 70 Test the hypothesis that there is no significant difference between the study habits and academic performance using a 0.05 level of significance.arrow_forwardA study in Sweden looked at former elite soccer players, people who had played soccer but not at the elite level, and people of the same age who did not play soccer. Here is a two-way table that classifies these subjects by whether or not they had arthritis of the hip or knee by their mid-fifties: Elite Non-elite Did not play Arthritis 10 9 24 No arthritis 61 206 548 Based on this study, you can conclude thatarrow_forwardA study is made of residents in Phoenix and its suburbs concerning the proportion of residents who subscribe to Sporting News. A random sample of 90 urban residents showed that 12 subscribed, and a random sample of 97 suburban residents showed that 17 subscribed. Does this indicate that a higher proportion of suburban residents subscribe to Sporting News? Use a 1% level of significancearrow_forward
- A study was performed on 200 elementary school students to investigate whether regular Vitamin A supplementation was effective in preventing colds during the month of March. 100 were randomized to receive daily Vitamin A supplements during the month of March, and 100 students were randomized to a placebo group (and did not receive Vitamin A) during the same month. The number of students getting at least one cold in March was computed in the two groups, and the results are given in the following 2 X 2 table. Using a 5% level of significance determine whether there is an association between Vitamin A supplementation and prevention of Common Cold ColdNo Cold Vitamin A1585100 Placebo2575100 40160200arrow_forwardAn experimental study was conducted on the effect of programmed materials in English on the performance of 20 selected college students. Before the program was implemented pretest was administered and after 5 months the same instrument was used to get the post-test result.arrow_forwardThe article “The Effects of a Low-Fat, Plant-Based DietaryIntervention on Body Weight, Metabolism, and InsulinSensitivity in Postmenopausal Women” (Amer. J. of Med.,2005: 991–997) reported on the results of an experiment inwhich half of the individuals in a group of 64 postmenopausaloverweight women were randomly assigned to a particularvegan diet, and the other half received a diet based on NationalCholesterol Education Program guidelines. The sample meandecrease in body weight for those on the vegan diet was 5.8kg, and the sample SD was 3.2, whereas for those on the control diet, the sample mean weight loss and standard deviationwere 3.8 and 2.8, respectively. Does it appear the true averageweight loss for the vegan diet exceeds that for the control dietby more than 1 kg? Carry out an appropriate test of hypotheses at significance level .05 based on calculating a P-valuearrow_forward
- An online clothing retailer is testing a new e-mail campaign by sending one version of the e-mail with the word “free” in the subject line (version A) to a group of 1,500 customers and another version of the e-mail with word “discount” in the subject line (version B) to a different group of 1500 customers. After tracking the responses to the two versions of the e-mail advertising, the retailer finds that 75 responded to version A and 105 responded to version B. At 0.05 significance level, can it be concluded that the response rate for version B is higher than the response rate to version A What is your decision? Enter “R” if your decision is to reject the null hypotheses. Enter “F” if the decision is fail to/do not reject the null hypotheses. Your answer (R/F) is: Which of the followings is the most appropriate conclusion for the hypotheses test? Enter the number corresponding to the most appropriate conclusion in the answer box. For example, if statement number 2 is the most…arrow_forwardAn online clothing retailer is testing a new e-mail campaign by sending one version of the e-mail with the word “free” in the subject line (version A) to a group of 1,500 customers and another version of the e-mail with word “discount” in the subject line (version B) to a different group of 1500 customers. After tracking the responses to the two versions of the e-mail advertising, the retailer finds that 75 responded to version A and 105 responded to version B. At 0.05 significance level, can it be concluded that the response rate for version B is higher than the response rate to version A Determine which of the following formulations of the hypotheses is appropriate and enter the corresponding number in the answer text box. Index “a” refers to the population of the customers who respond to version A and index “b” refers to the population of customers who are responsive to version B. Identify and enter the number corresponding to the most appropriate formulation for the…arrow_forwardA 1980 study investigated the relationship between the use of OCs and the development of endometrial cancer. The researchers found that of 117 endometrial-cancer patients, 6 had used the OC Oracon at some time in their lives, whereas 8 of the 395 controls had used this agent. Test for an association between the use of Oracon and the incidence of endometrial cancer, using a two-tailed test.arrow_forward
- To test the fairness of law enforcement in its area, a local citizens’ group wants to know whether women and men are unequally likely to get speeding tickets. Four hundred randomly selected adults were phoned and asked whether or not they had been cited for speeding in the last year. Using the results in the following table and a 0.02 level of significance, test the claim of the citizens’ group. Let men be Population 1 and let women be Population 2. Speeding Tickets Ticketed Not Ticketed Men 28 152 Women 20 200 Step 1 of 3: State the null and alternative hypotheses for the test. Fill in the blank below. H0: p1=p2 Ha: p1__p2 Step 2 of 3: Compute the value of the test statistic. Round your answer to two decimal places Step 3 of 3: Draw a conclusion and interpret the decision.arrow_forwardAronson and Mills (1959) conducted an experiment to see whether people's liking for a group is influenced by the severity of initiation. They reasoned that when people willingly undergo a severe initiation to become members of a group, they are motivated to think that the group membership must be worthwhile. Otherwise, they would experience cognitive dissonance: Why put up with severe initiation for the sake of a group membership that is worthless? In their experiment, participants were randomly assigned to one of three treatment groups: Group 1 (control) had no initiation. Group 2 (mild) had a mildly embarrassing initiation (reading words related to sex out loud). Group 3 (severe) had a severely embarrassing initiation (reading sexually explicit words and obscene words out loud). After the initiation, each person listened to a standard tape-recorded discussion among the group that they would now supposedly be invited to join; this was made up made to be as dull and banal as possible.…arrow_forwardA study was conducted to explore workplace bullying in a community NHS trust. Staff were asked about whether workplace bullying had affected their working environment (Quine L, BMJ 1999; 318: 228-229). Those who had been bullied had lower levels of job satisfaction (mean 10.5 [SD 2.7] vs 12.2 [2.3], P<0.001) and higher levels of job-induced stress (mean 22.5 [SD 6.1] v 16.9 [5.8], P<0.001) than those who had not been bullied. Based on the above info, Select which of the following statement(s) you believe to be true You CAN SELECT MORE THAN 1. a. The P value for the comparison of job-induced stress was less than 0.001. This means that we cannot reject the null hypothesis at the 5% level of significance. b. P < 0.001 means that there is a less than 1 in 1000 chance that we would have obtained these results, or more extreme results, if the alternative hypothesis was true. c. There is a significant difference in the levels of job satisfaction between…arrow_forward
- Holt Mcdougal Larson Pre-algebra: Student Edition...AlgebraISBN:9780547587776Author:HOLT MCDOUGALPublisher:HOLT MCDOUGAL