document.write( "Question 387293: A distribution of scores has µ = 40 and σ = 18
\n" ); document.write( "a. describe the distribution of sample means based on samples of n = 36 selected from this population (shape, central tendency, variability)
\n" ); document.write( "b. of all the possible samples of n = 36, what proportion will have sample means greater than 43?
\n" ); document.write( "c. of all the possible samples of n = 36, what proportion will have sample means less than 34?
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Algebra.Com's Answer #273781 by robertb(5830)\"\" \"About 
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a. n = 36, this is considered a large sample. For large samples, the Central Limit Theorem says that the distribution of the sample means is approximately normal (getting better as n gets higher and higher). The mean is \"mu+=+40\"and the variance \"%28%28sigma%29_X%29%5E2+=+sigma%5E2%2Fn\".\r
\n" ); document.write( "\n" ); document.write( "b. \"P%28X+%3E+43%29+=+P%28%28X+-+40%29%2F%2818%2Fsqrt%2836%29%29+%3E+%2843+-+40%29%2F3+=+1%29\". Hence \"P%28X+%3E+43%29+=+P%28Z+%3E+1%29+=+0.1587\".\r
\n" ); document.write( "\n" ); document.write( "c. \"P%28X+%3C+34%29+=+P%28%28X+-+40%29%2F%2818%2Fsqrt%2836%29%29%3E+%2834+-+40%29%2F3+=+-2%29\". Hence \"P%28X+%3C+34%29+=+P%28Z+%3C+-2%29+=+0.0228\".\r
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