A market researcher investigated cars and trucks sold in Canada to determine whether the proportions of sales for these two vehicle types were the same for all manufacturers. He examined randomly selected records for 50 sales of GM vehicles, 50 of Fords, 50 of Chryslers, 30 of Toyotas, and 20 of Volkswagens. (All sales were in December 1996.) The results are displayed below. At the 0.05 level of significance, test the claim that all these manufacturers sell cars and trucks in the same proportions.