Important ideas from the text : Application How much do college grades vary ? Indiana University Bloomington posts the grade distributions for its courses online .2 Students in Business Statistics in a recent semester received 45.7 % As , 36.2 % Bs 13.8 % Cs, 3.2% Ds , and 14 1.1 % Fs . Choose a Statistics 101 student at random . The student's grade on a four -point scale (with A = 4 ) is a random variable X with this probability distribution : Value Probability 0.011 0.032 0.138 0.362 0.457 1. Make a histogram of the probability distribution . Describe its shape 2. Calculate and interpret the mean of X. Show work . 3. The standard deviation is 0.879 . Interpret the standard deviation