In 2003, Brand A microwaves had 45% of the market, Brand B had 35%, and Brand C had 20%. This year the makers of Brand C launched a heavy advertising campaign. A random sample of appliance stores shows that, of 10,000 microwaves sold, 4,350 were Brand A, 3,450 were Brand B, and 2,200 were Brand C. Has the market changed? Test at 0.01.

Question

In 2003, Brand A microwaves had 45% of the market, Brand B had 35%, and Brand C had 20%. This year the makers of Brand C launched a heavy advertising campaign. A random sample of appliance stores shows that, of 10,000 microwaves sold, 4,350 were Brand A, 3,450 were Brand B, and 2,200 were Brand C. Has the market changed? Test at  0.01.

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The Answer of In 2003, Brand A microwaves had 45% of the market, Brand B had 35%, and Brand C had 20%. This year the makers of Brand C launched a heavy advertising campaign. A random sample of appliance stores shows that, of 10,000 microwaves sold, 4,350 were Brand A, 3,450 were Brand B, and 2,200 were Brand C. Has the market changed? Test at  0.01.

In 2003, Brand a Microwaves Had 45% of the Market