210 F23 HW6 Lec 3

Psych 210: Addington Fall 2023 Homework 6 (*13 points*) Due Date: Monday November 6 th by 4:00 PM at lecture A researcher wants a statistical test to be powerful, yet also would like to avoid a Type I error. For each of the following, state whether the approach would achieve the researcher’s goals, and explain your answer. 1. Increase the alpha level (for instance, from .01 to .05). 2. Use a small alpha level, but increase the sample size. 3. Use a one-tailed test. A clinical psychologist works at a mental health facility with patients who are severely emotionally disturbed. The patients on his floor all have a history of physical abuse as children. The psychologist is interested in whether these patients have a greater level of antisocial behavior compared to other emotionally disturbed individuals. The psychologist administers a well-known antisocial behavior inventory to his patients. This inventory has been given to a very large number of emotionally disturbed individuals, and the mean score for the inventory is  = 55 with a  = 12. Inventory scores are normally distributed, and a higher score indicates a greater level of antisocial behavior. Test whether the psychologist's patients have a significantly different level of antisocial behavior compared to the 'average' emotionally disturbed individual. Use an  of .01. Data from his patients are listed below: 59 67 89 81 83 83 85 60 65 73 71 83 84 78 60 90 74 71 88 86 79 4. State the null and alternative hypotheses. 5. Define the critical region(s) in terms of z-scores (not Ms). 6. Calculate the standard error and the observed z-score value. What is your decision regarding the null hypothesis? 7. State the conclusion in nonstatistical terms. Kerry investigates the effect of a new learning protocol on maze-running ability in mice. She knows that the mean time taken for mice to run a standardized maze in her lab is  = 50 seconds. Kerry runs a sample of 16 mice through her learning protocol; running times are listed below. 54 60 55 54 56 57 55 52 55 55 52 57 55 53 54 56 Test whether Kerry's new learning protocol makes her mice run significantly faster than average. Use an  of .05. 8. State the null and alternative hypotheses. 9. Determine the critical value(s) for t.