To assess the accuracy of a kitchen scale, a standard weight, known to weigh 1.000 gram, is weighed a total of n times, and the mean of the n weight measurements is computed. (If a 90% confidence interval for the mean calculated from these measurements does not contain 1.000, the scale is deemed inaccurate.) Suppose the scale readings are Normally distributed and that similar scales are known to measure such weights with a standard deviation of σ = 0.01 gram. Which of the following is the smallest value of n that will produce a 90% confidence interval with a margin of error of at most 0.001 grams?

AGRICULTURAL STATISTICS AND ECONOMICS

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Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]

To assess the accuracy of a kitchen scale, a standard weight, known to weigh 1.000 gram, is weighed a total of n times, and the mean of the n weight measurements is computed. (If a 90% confidence interval for the mean calculated from these measurements does not contain 1.000, the scale is deemed inaccurate.) Suppose the scale readings are Normally distributed and that similar scales are known to measure such weights with a standard deviation of = 0.01 gram. Which of the following is the smallest value of n that will produce a 90% confidence interval with a margin of error of at most 0.001 grams?

A	17
B	271
C	385
D	None of the above

Explanation:

Detailed explanation-1: -A random sample of 85 sixth-graders in a large city take a course designed to improve scores on a reading comprehension test. Based on this sample, a 90% confidence interval for the mean improvement in test scores for all sixth-graders in the city taking this course is found to be (12.6, 14.8).

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AGRICULTURAL STATISTICS AND ECONOMICS