Interns are complaining about either their internship stipend being very low or about the fact that they do not receive any stipend at all. To study this further, a lecturer selects a random sample of interns and his records show that the average salary of an intern is

$800 per month. Assume that the monthly salary of an intern is symmetrically distributed with a standard deviation of $245.

a. What is the percentage of interns earning less than $555 per month?

b. Determine the percentage of interns that earn between $1,290 and $1,535 per month.

c. If the lecturer denies the shape of the distribution in which it can be any distribution, what percentage of interns earn more than $1,000?