From looking at previous cell phone bills, a student notes that her calls per month follow an approximately normal distribution with a mean of 172 minutes and a standard deviation of 26 minutes.

a) Sketch a graph of the density function, indicating the values for the mean and standard deviation. (You do not need to determine the values of f(x) for the y­axis.)
b) The student is considering using a calling plan that allows 200 minutes per month free. Assuming the distribution from part (a) continues, what is the probability that the student will exceed 200 minutes in a month?

Astudent found the solution below for the given inequality. |x-9|< -4 x-9> 4 and x-9< -4 x> 13 and x< 5 which of the following explains whether the student is correct? -the student is completely correct because the student correctly wrote and solved the compound inequality. -the student is partially correct because only one part of the compound inequality is written correctly. -the student is partially correct because the student should have written the statements using “or” instead of “and.” -the student is completely incorrect because there is no solution to this inequality.