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A standard I.Q. test produces normally distributed results with a mean of 104 and a standard deviation of 16 for 52,000 students in grade 12 in the state. Approximately how many of these students would have I.Q.s above 140?

Respuesta :

Answer: approx 1196 students.

Step-by-step explanation:

As known for normal distribution 95.4% of all results are situating at +-2*s distance from the mean. (s is the standard deviation)

2s=16*2=32 . The mean +2s= 104+32=136 = approx 140.

95.4% from 52000 = 49608 students. The residual amont ( which is out of the border mean+-2s)= 52000-49608=2392

Because of the normal distribution simmetry the number of the students which has IQ 140 and more is twice less than 2392.

N=2392:2=1196

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