A professor knows that her statistics students' final exam scores have a mean of 79 and a standard deviation of 12.4. In his class, an "A" is any exam score of 90 or higher. This quarter she has 25 students in her class. What is the probability that 7 students or more will score an "A" on the final exam?

Americans (on average) individually eat 16 pounds of seafood each year with a standard deviation of 7 pounds.  James samples 40 Americans and finds and average of 14 pounds. How likely is it to get an average of 14 pounds if he had a representative sample?

A researcher wants to know that a random individual will fall between 107 and 103 .if the mean IQ is 100 the standard deviation is 15 what is the probability a random individual 's IQ will fall between 107 and 123?

You are deciding whether or to take Professor Smith or Professor Jones' advanced statistics class next semester. You know their grading range is the same 100 90 A, 89 80 B, 79 70 C, 69-60 D and failing is below 60. Both Professor's grades are distributed normally with Professor Smith's mean is 74 and standard deviation is 8.1 while Professor Jones' mean is 80 and standard deviation is 16.9.  a.) which professor gives a higher proportion of A's? (i.e., you should take this professor's class) b.) which professor gives a higher proportion of F's? (i.e. you should avoid this professor's class) How would I figure this problem out?