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In: Statistics and Probability

Researchers plan to study the weight gain of cows during a 3-month period. They wish to...

Researchers plan to study the weight gain of cows during a 3-month period. They wish to test at alpha = 0.01 if the mean weight gain exceeds 15 kg. Further, it is important for the researchers to detect if the mean weight gain is as large as 27 kg. An earlier study indicated that the standard deviation of the weight gains was around 14 kg. Since weight gains are normally distributed a t-test is to be used.

(a) If the researchers used a sample size of 22 what would be the power of the test in detecting if the mean weight gain is as large a 27 kg? Use R, showing the command you used and the result.

(b) Use Table 21 to determine the sample size required in order to have a power of 0.99 to detect if the mean weight gain is as large a 27 kg.

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orchestra answered 2 years ago
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