Explain when a z-test would be appropriate over a t-test.
DQ2 Week 3
Researchers routinely choose an alpha level of 0.05 for testing their hypotheses. What are some experiments for which you might want a lower alpha level (e.g., 0.01)? What are some situations in which you might accept a higher level (e.g., 0.1)?
EXERCISE 20 Questions to be Graded
1. Which patient scored the highest on the preoperative CVLT Acquisition? What was his or her T score?
2. Which patient scored the lowest on postoperative CVLT Retrieval? What was this patient's T score?
3. Did the patient in Question 2 have more of a memory performance decline than average on the CVLT Retrieval? Provide a rationale for your answer.
4. What is the mean () and standard deviation (SD) for preoperative T score for CVLT Acquisition?
5. Is the preoperative Retrieval T score for Patient 5 above or below the mean for the norm of the group? Provide a rationale for your answer.
6. Assuming that the distribution of the preoperative CVLT Retrieval T scores is normal, the middle 68% of the patients had T scores between what two values?
7. Assuming that the distribution of scores for the postoperative CVLT Retrieval T scores is normal, the middle 68% of the patients had T scores between what two values?
8. The researchers state that it appears that the functional integrity of the left temporal lobe, despite evidence of structural abnormality, plays a considerable role when it comes to memory outcomes following left ATL. Can the findings from this study be generalized to a larger population? Provide a rationale for your answer.
9. If a patient had a raw score = 30, what would his/her postoperative CVLT Retrieval T score be?
10. Did patients demonstrate more postoperative memory declines among CVLT Retrieval T scores than CVLT Acquisition T scores? Provide a rationale for your answer. (Grove 149)
Grove, Susan K. Statistics for Health Care Research: A Practical Workbook. W.B. Saunders Company,