HW5: 1) Assume we have conducted an experiment to test the hypothesis that marijuana affects the appetites of AIDS patients. The procedure and population are the same as we described previously,...

How much? How long?


HW5: 1) Assume we have conducted an experiment to test the hypothesis that marijuana affects the appetites of AIDS patients. The procedure and population are the same as we described previously, except this time we have sampled 12 AIDS patients. The results are shown here (the scores are in calories): a. What is the alternative hypothesis? b. What is the null hypothesis? C. Using α =0.05 2tail . What do you conclude? d. What error may you be making by your conclusion in part c? e. To what population does your conclusion apply? 2) A corporation psychologist believes that exercise affects self-image. To investigate this possibility, 14 employees of the corporation are randomly selected to participate in a jogging program. Before beginning the program, they are given a questionnaire that measures self-image. Then they begin the jogging program. The program consists of jogging at a moderately tax-ing rate for 20 minutes a day, 4 days a week. Each employee’s self-image is measured again after 2 months on the program. The results are shown here (the higher the score, the higher the self-image); a score of 20 is the highest score possible. a. What is the alternative hypothesis? b. What is the null hypothesis? C. Using α =0.05 2tail . What do you conclude? d. What error may you be making by your conclusion in part c? e. To what population does your conclusion apply? Page 3 of 3 STAT018 Dr. Sharona Atkins Spring 2019 3) A leading toothpaste manufacturer advertises that, in a recent medical study, 70% of the people tested had brighter teeth after using its tooth-paste (called Very Bright) as compared to using the leading competitor’s brand (called Brand X). The advertisement continues, “Therefore, use Very Bright and get brighter teeth.” In point of fact, the data upon which these statements were based were collected from a random sample of 10 employees from the manufacturer’s Pasadena plant. In the experiment, each employee used both toothpastes. Half of the employees used Brand X for 3 weeks, followed by Very Bright for the same time period. The other half used Very Bright rst, followed by Brand X. A brightness test was given at the end of each 3-week period. Thus, there were two scores for each employee, one from the brightness test following the use of Brand X and one following the use of Very Bright. The following table shows the scores (the higher, the brighter): a. What is the alternative hypothesis? b. What is the null hypothesis? C. Using α =0.05 1tail . What do you conclude? d. What error may you be making by your conclusion in part c? e. To what population does your conclusion apply? f. does the advertising seem misleading? 4) A researcher is interested in determining whether acupuncture affects pain tolerance. An experiment is performed in which 15 students are randomly chosen from a large pool of university undergraduate Page 3 of 3 STAT018 Dr. Sharona Atkins Spring 2019 volunteers. Each subject serves in two conditions. In both conditions, each subject receives a short-duration electric shock to the pulp of a tooth. The shock intensity is set to produce a moderate level of pain to the unanesthetized subject. After the shock is terminated, each subject rates the perceived level of pain on a scale of 0–10, with 10 being the highest level. In the experimental condition, each subject receives the appropriate acupuncture treatment prior to receiving the shock. The control condition is made as similar to the experimental condition as possible, except a placebo treatment is given instead of acupuncture. The two conditions are run on separate days at the same time of day. The pain ratings in the accompanying table are obtained. a. What is the alternative hypothesis? b. What is the null hypothesis? C. Using