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Important information about Z test for mean

Please provide an explanation and step by step process on how these answers are chosen.

In an article appearing in Today's Health a writer states that the average number of calories in a serving of popcorn is 75. To determine if the average number of calories in a serving of popcorn is different from 75, a nutritionist selected a random sample of 20 servings of popcorn and computed the sample mean number of calories per serving to be 78 with a sample standard deviation of 7.

State the null and alternative hypotheses.

A. H0: &#61549; = 75, H1: &#61549; &#8800; 75
B. H0: &#61549; &#8804; 75, H1: &#61549; > 75
C. H0: &#61549; &#8805; 75, H1: &#61549; < 75
D. H0: &#61549; = 75, H1: &#61549; > 75

Compute the z or t value of the sample test statistic.

A. z = 1.916
B. t = -1.916
C. t = 1.916
D. z = 1.645

At the &#61537; = .05 level of significance, does the nutritionist have enough evidence to reject the writer's claim?

A. No
B. Yes
C. Cannot determine

Solution Summary

The solution provides step by step method for the calculation of Z test statistic for mean . Formula for the calculation and Interpretations of the results are also included.

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