The Sampling Distribution of a Sample Mean
Sampling Distribution of the Mean
Answers
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The mean of the sampling distribution of the mean is the mean of the population from which the scores were sampled, in this case \(14\).
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The variance of the sampling distribution of the mean is the population variance divided by \(N\). The population SD is \(6\), so the population variance is \(36\). \(36/9 = 4\)
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The standard error is the standard deviation of the population divided by the square root of \(N\). In this case, \(12/4 = 3\)
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According to the central limit theorem, regardless of the shape of the parent population, the sampling distribution of the mean approaches a normal distribution as \(N\) increases. In this case, a sample size of \(30\) is sufficiently large to cause the sampling distribution of the mean to look about normal.
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Mean = \(75\), SD = \(2\), Skew = about \(0\): This problem is asking about the sampling distribution of the mean: Mean = \(75\), SD = \(10 \sqrt(25)\) = \(10/5\) = \(2\), Skew = about \(0\) because the central limit theorem states that the sampling distribution of the mean would be about normal with a large enough \(N\).