What is the z score for a score of 79 when the mean score of all persons who complete a depression scale is 89 and the standard deviation is 5?
Is a person with a score of 79 more or less depressed than most other people who complete the scale?
Use Table 4.3 (in your text) to find the following:
a. The area of the normal curve above a z score of 1.71.
b. The area of the normal curve between the mean and a z score of -1.34.
c. The z score of the normal curve that marks the 38th percentile
d. The z scores that mark the upper and lower limits of the middle 42 percent of the normal curve.
CASE STUDY: As an administrator of a local United Way agency, your job is to allocate funds for agencies that request them. Two agencies (A and B) require money from you so that they can stay in operation next year. Both offer the same services, but you have enough money to fund only one.
Agency A states that its clients had a mean treatment success score of 42 on a standardized measuring instrument that measures client functioning (N = 1,000).
Agency B, using the same measuring instrument, states that its mean treatment success score was 44 for the same period. Agency B also had 1,000 clients.
You take these data and calculate the appropriate statistic to determine whether sampling error played any role in the difference in scores. Your statistical analysis produces a finding of p < .25. Answer the following questions: Will you be able to use your statistical analysis to decide which agency to fund? Why? Discuss what additional information you would want before taking action on the study's results. Justify your answer.