Question 962665
P(Z < z) = 0.67 has the solution z = 0.4399


So P(Z < 0.4399) = 0.67 approximately


You use a calculator or table to determine this.


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z = (x-mu)/sigma


0.4399 = (11.54-10)/sigma


0.4399 = 1.54/sigma


0.4399*sigma = 1.54


sigma = 1.54/0.4399


sigma = 3.5007956


sigma = 3.50


The standard deviation is approximtely 3.50


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