In a survey of 280 adults over 50,80% said they were taking vitamin supplements.Find the margin of error for this survey if we want a 99% confidence in our estimate of the percent of adults over 50 who take vitamin supplements.

Question

Quizplus · Accepted Answer

To find the margin of error, we need to use the formula:

Margin of Error = z * (sqrt(p*q/n))

where p is the proportion of adults over 50 who take vitamin supplements (0.8), q is the complementary proportion (1 - 0.8 = 0.2), n is the sample size (280), and z is the z-score that corresponds to the desired level of confidence (99%).

Using a z-score calculator, we find that the z-score for a 99% confidence level is approximately 2.576.

Substituting the values into the formula, we get:

Margin of Error = 2.576 * (sqrt(0.8*0.2/280)) = 0.0616 or 6.16%

Therefore, the best choice is C, with a margin of error of 6.16%.

In a Survey of 280 Adults Over 50,80% Said They