Question 1189289
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You have the correct values for {{{mu = 28.5}}} and {{{sigma = 2.67}}} approximately.


I'm assuming you meant to say *[Tex \Large P(\mu - \sigma < X < \mu + \sigma)] I replaced the lowercase x's with mu's.


If that's what your teacher wants, then I'm not sure how your book got 0.740


According to the Empirical Rule, it should be roughly 0.68 since about 68% of the population is within 1 standard deviation of the mean. The more accurate value is roughly 0.6826894921 which unfortunately is nowhere close to 0.740


Perhaps my assumption made at the top of this page is incorrect. If it is, then please let me know. 
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