1. Full-time Ph. D students receive an average of $12837 per year. If the average salaries
are normally distributed with a standard deviation of $ 1500, find these probabilities.
(a) The student makes more than $ 16000
(b) The student makes between $13000 and $15000
2. Each month an American household generates an average of 28 pounds of newspaper
for garbage or recycling . Assume the variable is approximately normally distributed and
standard deviation is 2 pound. If a household is selected at random, find the probability of
its generating
(a) Between 26 and 32 pounds per month
(b) More than 30.4 pounds
3.For a medical study researcher wishes to select people in the middle 60 %of the
population based on blood pressure .Assume the blood pressure readings are normally
distributed and the mean systolic blood pressure is 120 and standard deviation is 8. Find
the upper and lower readings that would qualify people to participate in the study.