People with z-scores above 2.5 on an IQ test are sometimes classified as geniuses. If IQ scores have a mean of 100 and a standard deviation of 16 points, what IQ score do you need to be considered a genius?

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Answer 1 · 2017-09-18T12:17:05

#140#

we have

#X~N(100,16^2)#

and are given

#P(Z>2.5)---(1)#

to find the required #X #score

we have to standardise

#P(z>(X-100)/16)---(2)#

comparing #(1)" & "(2)#

#=>(X-100)/16=2.5#

#:.X-100=16xx2.5=40#

#X=100+40=140#