find the mean, variance and standarddeviation of each data set.
a. 4, 6, 7, 7, 5, 1, 2, 3
b. 2, 5, 8, 7, 1, 3, 9, 11, 4, 2
c. -4, -2, -0, 3, -5
d. 1, 2, 3, 4, 3, 500
e. 1, 2, 3, 4, 3