Question

The final marks in a statistics course are normally distributed with a mean of 70 and a standard deviation of 10. The professor must convert all marks to letter grades. She decides that she wants 10%A’s, 30%B’s, 40%C’s, 15%D’s, and 5%F’s. Determine the cutoffs for each letter grade

Answer 1

Use inversenormal on a calculator and type in .1 , 70 , 10 . That percent is for A and will determine at what mark an A will be. Do the same for the rest of the grades but change the first argument in the calculation