SOLUTION: if the mean is 266 and standard deviation is 12 and the question is asking what percentage last more than 283: p(x>283). how do i do this

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Question 1201312: if the mean is 266 and standard deviation is 12 and the question is asking what percentage last more than 283: p(x>283). how do i do this
Answer by math_helper(2461) About Me  (Show Source):
You can put this solution on YOUR website!


Calculate the z-score:  (283-266)/12 = 1.41667



Now find a positive z-table and go down to row "1.4" and across to column "0.02"  (rounded 1.41667 to 1.42).  You will see  0.92220.



This number is the fraction less than 283.  You stated you want P(x>283) so you take 1-0.92220 to get 0.0778.  

Converting this to a percentage,  7.78% of the samples will be greater than 283.