Question 905928
a. z = invNorm(.90) = (X-500)/100
100invNorm(.90) + 500 = X, score would you use as a cutoff score
b. 
100invNorm(.15) + 500 = X, verbal GRE score corresponds to a percentile rank of 15%
z = (628-500)/100 = 128/100 = 1.28
normalcdf(-100, 1.28)