HP340: Statistical Methods, Spring 2015Due: 3:30 p.m., Tuesday Mar 24, 2015Homework 7Total Points: 25Show your work/explain your reasoning when calculations are required. Late assignments will not be accepted. 1. (3 points total) For each of the following studies, indicate the analysis type from the choices below:A. Independent groups t-test B. Related groups t-test C. NeitherC To determine customer satisfaction at a particular coffee shop, randomly selected customers were asked to rate their experience on a scale from 1 to 5. They wanted to see if the mean satisfaction score at this particular coffee shop was at least "4".B To see if stress for incoming college freshman is reduced during their second semester, new USCstudents were given a stress survey at the end of both their fall and spring semesters. Investigators compared scores from the two surveys.A To see if Lipitor is useful at reducing cholesterol levels, a doctor gives half of his patients with highcholesterol Lipitor and the other half a placebo. Cholesterol levels from all patients were measured after two moths of treatment, and the data were analyzed to compare the groups.2. (10 points total) Researchers want to investigate the effect of media depiction of female beauty on teenage girls aged 15-19 by comparing self-image after viewing photographs of “regular” women versus photographs of idealized feminine beauty. Subjects were provided with a self-image questionnaire after viewing the images, with higher scores representing a more positive self-image. The 34 subjects in the group that saw the standard photographs had a mean self-image rating of 18.7with s1= 5.5, whereas the 37 subjects in the group that saw the media-type images had a mean self-image rating of 18.0 with s2 = 5.4.a. Is this a between-subjects or within-subjects research design?Between-subjects because the subjects had two different variables. One group saw one ad while the other saw a different one.b. Provide the null and alternative hypothesis to find if there is a significant difference in the mean self-image rating between the two groups.Null: The mean self-image rating does not change between the two groups.Alternative: The mean self-image rating does change between the two groups.c. Conduct a two-tailed test and indicate the observed t-statistic and critical value for α=0.05.(attached in picture)d. Write a brief conclusion based on your findings. (below)1 / 33. (12 points total) It seems when people are under stress they are more likely to make errors in pronunciation. A group of students hypothesized that discussing a stressful topic would decrease the likelihood of someone clearly enunciating their words. To test this hypothesis, they first recorded students talking about a non-stressful topic, and then they recorded the same students talking about a stressful topic. They identified the number of words that were not fully enunciated for the first 100 words each subject uttered in each condition. The results from the 11 participants are presented here:StudentNon-stressful(before)Stressful(after)11 222 230 345 653 262 371 384 596 7107 7112 4a. What test is appropriate for testing whether stress may influence enunciation using these data?We would use a two-sided, non-directional, t-testb. State the null and alternative hypothesis both in words and in equations.Null: There is no difference in enunciation regardless of the stress level.Alternative: There is a difference in annunciation regardless of the stress level.2 / 3H0: μstressful=μnon-stressfulH1: μstressful-μnon-tressful≠0c. Conduct a two-tailed test at a α=0.05 significance level:I. By hand using a calculator (attached in picture)II. Using the statistical software JMPd. Write a brief conclusion based on your findings.3 /