Find the mean and standard deviation.
Hypersexual behaviour caused by traumatic brain injury (TBI) is often treated with the drug DepoProvera. In one clinical study, eight young male TBI patients who exhibited hypersexual behaviour were treated weekly with 400 mgs of DepoProvera for six months. The testosterone levels [in ng/DL] prior to treatment and at the end of the 6month treatment period are given in the table below.
Patient

PreTreatment

After 6 months on DepoProvera

1
2
3
4
5
6
7
8

849
903
890
1,092
362
900
1,006
672

96
41
31
124
46
53
113
174

Form the column of differences and find out the mean and standard deviation of this column of numbers.