Suppose you know that the heights of elementary school students in
southern Kenya follow a normal probability distribution with a mean of
40.1 inches and a (population) standard deviation of 2.2 inches.
What
is the probability that an elementary school student in southern Kenya
is greater than or equal to 41.3 inches tall? (Round to the nearest
percent.)
z score is (x  mean)/standard deviation
so (41.3  40.1)/2.2
 and look up that on a standard normal distribution chart
 zchart
 to that value for z (.55) is .7088

that is the probability of LESS than z(.55)
So you take 1 .7088 to get .2912
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