In: Statistics and Probability
The Intelligence Quotient (IQ) test scores are normally distributed with a mean of 100 and a standard deviation of 15. Given a class with 12 students, what is the probability that the class' average IQ score is less than 115?
Solution :
Given that ,
mean = = 100
standard deviation = = 15
n = 12
= 100
= / n =15 / 12=4.3301
P( <115 ) = P[( - ) / < (115 -100) / 4.3301]
= P(z <3.46 )
Using z table
= 0.9997
probability= 0.9997