Two companies A and B have recently conducted aggressive advertising campaigns in order

to maintain and possibly increase their respective shares of the market for fabric softener.

Before the adverts began, the market share of company A was 45%, company B was 40% and

other competitors accounted for the remaining 15%. To determine whether these market

shares changed after the campaigns, a marketing analyst solicited the preferences of a random

sample of 200 customers of fabric softener. Of the 200 customers, 102 indicated a preference

for company A, 82 preferred company B and the remaining 16 preferred the products of one

of the competitors'. Can the analyst infer at the 5% significance level that the customer

preferences have changed from their levels before the advertising campaigns were launched?