After computing a confidence interval, the investigator believes that the results are meaningless because the width of the interval is too large. In reconstructing the interval,
The investigator should
A) decrease the sample size
B) increase the level of confidence
C) increase the sample size
D) reduce the population variance
E) none of the above

Question

Quizplus · Accepted Answer

Increasing the sample size will reduce the width of the confidence interval. This is because as sample size increases, the standard error of the estimate decreases. Decreasing the sample size will likely increase the width of the confidence interval. Increasing the level of confidence or reducing the population variance may have some effect on the width of the interval, but these measures would not be as effective as increasing the sample size.

After Computing a Confidence Interval, the Investigator Believes That the Results