Suppose that Os are distributed normallv in a certain pediatric population with
mean 100 and standard deviation of 15
what proportion of the population will have 10s less than 902
The blue shaded bars in the histogram represents the proportion of the score in the
observed data that are less than or equal to 90
Total: N=1015
0 <90 • ^ 256 25 22%)
what proportion will have IQs greater than 145?
According to 68-95-99./ OR empirical rule.
Approximately 0.3% of the proportion has IQs greater than 145
3. what is the IQ cutoff in the top 5% in this pediatric population?
Z score = value - mean / Standard deviation
4. what will be the 95% reference ranges for IQs in this pediatric population?
IQ scores are normally distributed with a mean of 100 and a standard deviation of
15
© About 68 % of individual have IQ score in the internal
100+-(15) = [85, 115 ]
©About 95% of individual have IQ score in the interval
100 +-2(15) =[70.1301
©About 99.7% of the individual have IQ score in the interval
100+-3(15) =[55,1451.