The upper limit of a confidence interval at the 99% level of confidence for the population proportion if a sample of size 100 had 40 successes is:
A) 0.3040.
B) 0.4047.
C) 0.4960.
D) 0.4806.

Question

Quizplus · Accepted Answer

The sample proportion is 0.4. Using the formula for the confidence interval for a proportion, the upper limit is calculated as 0.4 + (Z * sqrt((0.4*(1-0.4))/100)), where Z is the Z-score for 99% confidence level (approximately 2.576). This gives approximately 0.4960.

The Upper Limit of a Confidence Interval at the 99