1 A company claim that the mean life and standard deviation

1. A company claim that the mean life and standard deviation of the bulbs are 360 hours and 90 hours respectively. A sample of 625 bulbs is chosen. It is found that the mean life and standard deviation of the bulb in the sample are 355 hour and 90 hours respectively. Use these results to test the claim at the 5% level of significance

The Pew Research Center claims that more than 55% of American adults regularly watch a network news broadcast. You decide to test this claim and ask a random sample of 425 Americans whether they regularly watch a network news broadcast. Of the 425 Americans, 255 responded yes. At a = 0.05, is there enough evidence to support the claim?

A random sample has mean height of 80 boys, who participated in the athletic competition was 167 cm with a standard deviation of 9 cm. The mean height of the 160 boys who did not participate in the athletic competition was 163 cm with a standard deviation of 10 cm. test the hypothesis at 5% level of significance, whether the boys who participate in athletics are taller than the other.

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