The mayor of a large city claims that 25 % of the families in the city earn more than $ 100,000 per year; 55 % earn between $ 30,000 and $ 100,000 (inclusive); 20 % earn less than $ 30,000 per year.
In order to test the mayor's claim, 285 families from the city are surveyed and it is found that:
90 of the families earn more than $ 100,000 per year;
135 of the families earn between $ 30,000 and $ 100,000 per year (inclusive);
60 of the families earn less $ 30,000.
Test the mayor's claim based on 2.5 % significance level.