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Posted by Christine on Sunday, May 16, 2010 at 8:55pm.

assume that a set of test scores is normally distributed with a mean of 100 and a standard devaiton of 20. Use the 68-95-99.7 rule to find the following quantities: a. percentage of scores greater than 120

would the percentage of scores greater than 120 be 4.865 or 4.87

Z = (120-100)/20 = 20/20 = +1 Of the 50% higher than the mean, Z = +1 gives you 50 - 1/2(68) = 50 - 34 =?

16

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