If a researcher wishes to increase the confidence level from 95% to 99%,what approximately will be the effect on sample size?
A)The sample size will decrease in proportion to the increase in the confidence level.
B)The ratio of the new sample size to the old is 3/2.
C)The ratio of the new sample size to the old is 2/3.
D)The ratio of the new sample size to the old is 9/4.
E)The ratio of the new sample size to the old is 4/9.

Question

Quizplus · Accepted Answer

The effect of increasing the confidence level from 95% to 99% will require an increase in sample size. The ratio of the new sample size to the old can be found using the formula: (zα/2 × σ / E)^2. When we calculate this ratio for 99% confidence and 95% confidence, we get (2.58/1.96)^2 = 2.25, which means the new sample size will be 9/4 times the old sample size (or a 125% increase). Therefore, the correct answer is D.

If a Researcher Wishes to Increase the Confidence Level from 95