Question

Assume that adults have IQ scores that are normally distributed with a mean of 95.8 and a standard deviation of 22.4. Find the probability that a randomly selected adult has an IQ greater than 127.6. ​(Hint: Draw a​ graph.) The probability that a randomly selected adult from this group has an IQ greater than 127.6 is nothing. ​(Round to four decimal places as​ needed.)

Answer 1

Since the distribution is normal hence Z score is applicable for probability calculation as

P(X>127.6)

Z score at X=127.6

Hence P(X>127.6) =P(Z>1.42) is computed using Z table shown below as

=0.0778