5. a. b. C. Compute the independent measures t-test. Report the degrees of freedom and the value of the t. Using a two-tailed test with a = .05, what is your decision? (reject the null hypothesis or fail to reject the null hypothesis) Calculate Cohen's d to measure the effect size. Loftus and Palmer conducted a classic study demonstrating how the language used to ask a question can influence eyewitness memory. In the study, college students watched a film of an automobile accident and then were asked questions about what they saw. One group was asked, "About how fast were the cars going when they smashed into each other?" Another group was asked the same question, except the verb was changed to "hit" instead of "smashed into." Suppose a researcher repeats this study with a sample of college students and obtains the following results: Estimated Speed Smashed into n = 11 Hit n = 11 M = 39 a. b. C. PR d. e. M = 45 S₁²= 30 S2² = 36 Compute the independent measures t-test. Report the degrees of freedom and the value of the t. Using a two-tailed test with a = .05, what is your decision? (reject the null hypothesis or fail to reject the null hypothesis) Calculate r² to measure effect size. Now increase the variability by doubling the variances to s₁² = 60 and s₂² = 72. Report the independent measures t-test, your decision (reject or fail to reject the null), and the measure of effect size (r²). Comparing your answers for parts a and d, describe how sample variability influences the outcome of the hypothesis test and the measure of effect size. 1. 2. One sample has SS = 117 and a second sample has SS = 81. a. b. If n 10 for both samples, find each of the sample variances, and calculate the pooled variance. Because the samples are the same size, you should find that the pooled variance is exactly halfway between the two sample variances. Now assume that n = 20 for the first sample and n = 10 for the second. Again, calculate and report the two sample variances and the pooled variance. You should find that the pooled variance is closer to the variance for the larger sample. Two separate samples receive different treatments. After treatment, the first sample has n = 5 with SS 60, and the second has n = 11 with SS = 110. a. Compute the pooled variance for the two samples. b. Calculate the estimated standard error for the sample mean difference. C. Assume that the mean difference between the samples is 3 points. Compute the independent measures t-test. 3. 4. d. Using a two-tailed test with a = .05, what is your decision? (reject the null hypothesis or fail to reject the null hypothesis) Does posting calorie content for menu items affect people's choices in fast-food restaurants? Researchers monitored the calorie content of food purchases for adolescents. Half of the adolescents were monitored while making food purchases where calorie content was provided, whereas the other half made food purchases where calorie content was not provided. When calorie content was present, the results showed an average of M = 800 calories per meal with s = 80 for n = 10. When calorie content was not present, the results showed an average of M = 900 calories per meal with s = 100 for n = 12. a. b. C. d. Compute the independent measures t-test. Report the degrees of freedom and the value of the t. Using a two-tailed test with a = .05, what is your decision? (reject the null hypothesis or fail to reject the null hypothesis) Calculate Cohen's d to measure the effect size. Construct a 95% confidence interval to estimate the size of the population mean difference. Binge-watching a television show might not be the best way to enjoy a television series. Participants in an experiment watched an entire television series in the laboratory during either daily one-hour sessions or a single binge session. Participants were asked to rate their enjoyment of the television series on a scale of 0 to 100. Data are listed below: Binge-watched Daily-watched 85 80 86 95 76 84 75 79 83 77 70 87 85 93