If anyone can help me I will be forever greatful.

The problems I am working with are below..

here are the problems I'm working with..

The first question, all it states is...

A nationally standardized test is scaled so that the normally distributed scores have a mean of 75 and a standard deviation of 5 in the population.

a. If you randomly select a person who has taken this test, what is the probability that their scores will be 80 or higher?
b. 75 or lower
c. 68 or lower
d. 84 or lower
e. between 60 and 85

2. IF we have a group of 25 scores from this test, and compute the mean, what is the probability that this mean will be:
a. below 76?
b. below 73?
c. above 75?

Boy-it's been a long time since I had to do stats. What's the definition of standard deviation for these problems?

(what percentage is it?)