An airline is interested in determining the proportion of its customers who are flying for reasons of business. If they want to be 90% certain that their estimate will be correct to within 2 percent, how large a random sample should they select?

a random sample they should select should be 1692 large.

Explanation:

Given:

a = 0.1

Z (0.05) = 1.645 (from standard normal table)

n = (Z/E) ^2*p * (1 - p)

= (1.645/0.02) ^2*0.5*0.5

= 1691.266

Therefore, a random sample they should select should be 1692 large.