Exercise 3-114

The final marks for the Wednesday class in Statistics 101 are ready to be posted. The class average is 60%, with a standard deviation of 10.The distribution of grades is approximately bell-shaped.(Round the final answers to 2 decimal places.)

a.What percentage of the grades are above 90?

Percentage of grades%

b.What percentage of the grades are below 50?

Percentage of grades%

c.What percentage of the grades are between 50 and 70?

Percentage of grades%

d.What percentage of the grades are between 50 and 80?

Percentage of grades%

e.What percentage of the grades are between 50 and 90?

Percentage of grades%

f.What percentage of the grades are less than 50 or more than 80?

Percentage of grades%