A genius society requires an IQ that is in the top 2% of the population in order to join. If an IQ test has a mean of 100 and a standard deviation of 15, what is the minimum qualifying score to join the genius society?

Question

anonymous · Answer

we need Pr(X > x) = 0.02 

which is like:  pr(X<x) = 0.98 

We will determine z: pr(Z<z) = 0.98 

and in place of the table, I will just type it

=norminv(0.98,0,1) 
which gives the number z satisfying Pr(Z<z) = 0.98 

Result is 2.053748176 

so 

x - 100 
▬▬▬..=...2.053748176 

15 

x = 2.053748176(15) + 100 = 130.8

anonymous · Answer

That is correct.  The answer is 130.  I just got my score back from test result and it is 130. :)