SOLUTION: An IQ test is designed so that the mean is 100 and the standard deviation is 25 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of
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Question 1128917: An IQ test is designed so that the mean is 100 and the standard deviation is 25 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of statistics students such that it can be said with 90% confidence that the sample mean is within 5 IQ points of the true mean. Assume that sigma=25 and determine the required sample size using technology. Then determine if this is a reasonable sample size for a real world calculation.
The required sampole size is ____
Would it be reasonable to sample this number of students?
Yes. This number of IQ test scores is a fairly small number.
Yes. This number of IQ test scores is a fairly large number.
No. This number of IQ test scores is a fairly large number.
No. This number of IQ test scores is a fairly small number. Answer by rothauserc(4718) (Show Source):
You can put this solution on YOUR website! The z-score for a 90% confidence level is 1.645
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Necessary Sample Size = (Z-score * StdDev / (margin of error))^2
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Margin of Error is 5
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Necessary Sample Size = (1.645 * 25 / 5)^2 = 67.6506 is approximately 68
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Yes. This number of IQ test scores is a fairly large number.
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Note The necessary sample size of 68 is > 30, which will allow the use of the Normal Distribution
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