Question

A psychologist is interested in the conditions that affect the number of dreams per month that people report in which they are alone. We will assume that based on extensive previous research, it is known that in the general population the number of such dreams per month follows a normal curve, with mean (μ) = 5 and standard deviation (σ) = 4. The researcher wants to test the prediction that the number of such dreams will be greater among people who have recently experienced a traumatic event. Thus, the psychologist studies 36 individuals who have recently experienced a traumatic event, having them keep a record of their dreams for a month. Their mean number of alone dreams is 8. Should you conclude that people who have recently had a traumatic experience have a significantly different number of dreams in which they are alone? Carry out the full five steps of hypothesis testing for a two-tailed test. In step V, sketch the comparison distribution. Label the mean with both a Z and a raw score. Draw in the significance level 0.05 (cutoff) and label with Z-scores. Label the percent of the area cut-off. Indicate the position of the sample mean and label it with both a Z and a raw score.

Step I: Restate the Question. Population 1:

Population 2 :

Research hypothesis :

Null hypothesis (2 points):

Step II: Give the characteristics of the comparison distribution .

Step III: Give the cut-off sample score(s) .

Step IV: Determine the sample score on the comparison distribution .

Step V(a): Sketch the comparison distribution (cut-off & computed values) and give the decision .

  

Step V(b): Compute the 99% confidence intervals .

lower limit=

upper limit=

Answer 1