It is assumed that the test results for a class follow a normal distribution with a mean of 78 and

a standard deviation of 36.

1.What is the probability of a student obtaining the a grade higher than 72?

2.Calculate the percentage of students who have scores that are at least five points higher than

the score that marks the border between pass and fail (a failing grade is defined as 25% of the

tests with the lowest scores) .

3.what is the probability that it is greater than 84?