Assume that adult have Q scores that are normally distribute

Assume that adult have Q scores that are normally distributed with a mean of mu = 105 and a standard division 0.20. find the probability that a randomly select adult has an IQ less than 145. The probability that a randomly selected adult has an IQ less than 145 is

Solution

We first get the z score for the critical value. As z = (x - u) / s, then as          
          
x = critical value =    145      
u = mean =    105      
          
s = standard deviation =    20      
          
Thus,          
          
z = (x - u) / s =    2      
          
Thus, using a table/technology, the left tailed area of this is          
          
P(z <   2   ) =    0.9772 [ANSWER]