I need help with these two question from my practice final exam. I had trouble with these two problems on my midterm as well and need help knowing how to solve them.

-A population is normally distributed with mean 28.9 and standard deviation 3.8.

a) Find the intervals representing one, two, and three standard deviations from the mean.

b) What percentage of the data lies in each of the intervals in (a) above.

-The scores on a certain class exam are normally distibuted with mean score of 68 and standard deviation 9.

a. What is the probability that a score is above 68.

b. What is the probability that a score is below 68.

c. What is the probability that a score is between 68 and 90.

d. What is the probability that a score is above 85.

e. What is the probability that a score is between 62 and 85.

f. What is the minimum score requires to place in the top 5% of the class.

g. A test with a score below ________ will place in the bottom 10% of the class.