Find the z score corresponding to P37.
We are asked to find the z-score associated with P37 (or a probability of 37%).
We can use a graphing utility or statistics package to find this value. (My calculator gives z=-.3318533512)
Alternatively we can use a standard normal table -- we look through the table to find a value near .3700. We find .3707 at -0.33 and .3669 at -0.34, so we take the closer value of -0.33.
So z is approximately -0.33
Note that this makes sense as .37 is less than .5 so the z value is negative.