Chapters 1 - 4
Farmingdale State College
A psychology researcher collects the following data on the number of hours five participants spent practicing a task: 3, 5, 8, 2, 7.
Question: What is the mean number of hours spent practicing?
A study measures the changes in mood scores before and after an intervention. The changes in mood scores are: -4, -2, 0, 3, 5.
Question: Calculate the mean change in mood score.
A psychologist measures the number of stressful events experienced by a small group of participants over a week: 2, 3, 6, 4, 5.
Question: Calculate the standard deviation of stressful events.
Sample Standard Deviation Participants’ anxiety scores in a clinical trial are recorded as: 4, 7, 3, 5, 8, 6, 2.
Question: Compute the standard deviation of these anxiety scores.
A researcher finds that the standard deviation of reaction times in a cognitive task is 1.5 seconds. Another researcher finds a standard deviation of 0.5 seconds for a similar task.
Question: Which task shows more variability in participants’ reaction times, and what might this indicate about task difficulty?
In a personality study, the average score on an extraversion scale is 50, with a standard deviation of 10. One participant scores 70.
Question: What is the Z-score for this participant?
A participant in a self-esteem survey has a Z-score of -1.5. The mean self-esteem score for the survey is 40, and the standard deviation is 5.
Question: Did this participant score above or below the mean, and by how many standard deviations?
The mean stress score of a group is 25, with a standard deviation of 4. If a participant has a stress score of 18,
Question: Calculate their Z-score and interpret its meaning in the context of stress levels.
In a clinical assessment, the average depression score is 60, with a standard deviation of 8. Two participants have scores of 72 and 48.
Question: Calculate the Z-scores for both participants and explain what the values tell us about their relative positions in the group.