The paper “Growth Hormone Treatment for Short Stature” (New England Journal of Medicine...

The paper “Growth Hormone Treatment for Short Stature” (New England Journal of Medicine [October 27, 1983]: 1016–1022) gives the accompanying data for height velocity before growth hormone therapy and during growth hormone therapy for 14 children with hypopituitarism.

a. Use a level .05 signed-rank test to decide if growth hormone therapy is successful in increasing the mean height velocity.

b. What assumption about the height velocity distributions must be made in order for the analysis in Part (a) to be valid?