# Answer to Question #24631 in Statistics and Probability for Ellie

Question #24631

The mean IQ score for 1500 students is 100, with a standard deviation of 15. Assuming the scores have a normal curve,

how many have an IQ between 85 and 115?

how many have an IQ between 85 and 115?

Expert's answer

z(115) = (115-100)/15 = 1

z(85) = (85-100)/15 = -1

We need to consult Z-table to find P-value with current Z values

P(85< x < 115) = P(-1< z < 1) = 0.6827

# of 1500 that have IQ between 85 and 115 = 0.6827*1500 ~ 1024

z(85) = (85-100)/15 = -1

We need to consult Z-table to find P-value with current Z values

P(85< x < 115) = P(-1< z < 1) = 0.6827

# of 1500 that have IQ between 85 and 115 = 0.6827*1500 ~ 1024

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