Research/Statistics MCQs



Research/Statistics MCQs

Explanation of Answers

1 Answer = E

A. Power is related to sample size and is a measure of the probability that the study will be able to detect a statistically significant difference if a difference truly exists. In this case a significant p value was found so the power was adequate.

B. The p value looks highly significant but the 95% confidence interval ranges from –2% to +12%. In other words there is a 95% chance that the actual mean improvement due to Drug X is in the range –2% to +12%. So, there is a chance that Drug X actually decreases survival. When you see a confidence interval pass through zero, reject the study because the results are inconclusive.

C. The –2% end of the confidence interval is the lower end of the 95% range of possible means. There is a 2.5% chance that the actual mean is even worse than –2% but without seeing the raw study data we have no idea what proportion of patients had decreased survival.

D. The p value ................
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