For a standard normal distribution, find the percentage of data that are

a. within 1 standard deviation of the mean.

b. within 1.96 standard deviations of the mean.

c. between m 2 3s and m 1 3s.

d. between 1 standard deviation below the mean and 2 standard deviations above the mean.

e. more than 2 standard deviations away from the mean.