Question

The marketing department must estimate the percent of the website's current viewers who prefer a new website design. If the researcher wants to be 95% confident that the margin of error does not exceed 0.095 in estimating the true proportion, how large a sample must be pickeď?

a)601

b)107

c)186

d)250

Answer 1

Margin of error = e = 0.095

Confidence level = c = 0.95

Consider proportion = p = 0.5

Sample size (n) :

where zc is z critical value for (1+c)/2 = (1+0.95)/2 = 0.975

zc = 1.96 (From statistical table of z values)

n = 106.4155

n = 107 (Round to next integer)

Sample size = n = 107