"Suppose that over a year the daily percent change (+ or -) for the S&P 500 adjusted closing value is approximately normally distributed with a mean of +0.04% and a standard deviation of 0.90%. DON'T USE EXCEL FORMULAS"
A) What is the 1st quartile of the percent change?
B) The 80th percentile?
Can you please show me step by step how to solve these questions?