HW 8:
1) (2 pts) Write a function to compute the mean of a vector. Name
your function mymean and generate your own test case.
2) (2 pts) Write a function to compute the standard deviation of a vector
Name your function mystd and generate your own test case.
3) (2 pts) Modify the function you wrote for Problem 3 in HW 7 to use these
two new functions.