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A food magazine decided to test the accuracy of Chips-a-ton's slogan: "Two thousand chocolate chips in every bag." Magazine employees counted the number of chocolate chips in 100100 randomly selected Chips-a-ton bags. The magazine found a 90%90\% confidence interval of for the mean number of chocolate chips in Chips-a-ton bags.\newlineIs the following conclusion valid?\newlineIf 100100 more samples are taken (with elements chosen randomly and independently), it is expected that exactly 9090 of them will each produce a 90%90\% confidence interval that contains its sample mean.\newlineChoices:\newline(A)yes\newline(B)no\newline

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Q. A food magazine decided to test the accuracy of Chips-a-ton's slogan: "Two thousand chocolate chips in every bag." Magazine employees counted the number of chocolate chips in 100100 randomly selected Chips-a-ton bags. The magazine found a 90%90\% confidence interval of for the mean number of chocolate chips in Chips-a-ton bags.\newlineIs the following conclusion valid?\newlineIf 100100 more samples are taken (with elements chosen randomly and independently), it is expected that exactly 9090 of them will each produce a 90%90\% confidence interval that contains its sample mean.\newlineChoices:\newline(A)yes\newline(B)no\newline
  1. Definition of 9090% Confidence Interval: A 90%90\% confidence interval means that if we were to take many samples and calculate the confidence interval for each, we would expect 90%90\% of those intervals to contain the true population mean, not necessarily the sample mean.
  2. Misunderstanding of Confidence Intervals: The conclusion that exactly 9090 out of 100100 additional samples will produce a 90%90\% confidence interval containing their sample mean is a misunderstanding of confidence intervals.
  3. Focus on Population Mean: Confidence intervals are about the population mean, not the sample mean. The statement is incorrect because it guarantees a specific outcome for a random process, which is not how confidence intervals work.

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