Pig castration study. Two methods of castrating male piglets were investigated in Applied...

Pig castration study. Two methods of castrating male piglets were investigated in Applied Animal Behaviour Science (Nov. 1, 2000). Method 1 involved an incision in the spermatic cords, while Method 2 involved pulling and severing the cords. Forty-nine male piglets were randomly allocated to one of the two methods. During castration, the researchers measured the number of high-frequency vocal responses (squeals) per second over a 5-second period. The data are summarized in the accompanying table. Conduct a test of hypothesis to determine whether the population mean number of high-frequency vocal responses differs for piglets castrated by the two methods. Use α = .05.

Based on Taylor, A. A., and Weary, D. M. “Vocal responses of piglets to castration: Identifying procedural sources of pain.” Applied Animal Behaviour Science, Vol. 70, No. 1, November 1, 2000.