2.6. A study of prison violence examined the effects of two independent variables—percent of inmates sentenced for a violent crime (x1) and average amount of space per inmate (x2)—on the average number of violent acts per day ( y). All variables were measured for a random selection of cell blocks in three prisons. The researcher reported the following results: ry,x1 ¼ 0:20 ry,x2 ¼ 0:20 rx1,x2 ¼ 0:20 sy ¼ 0:35 sx1 ¼ 10:52 sx2 ¼ 2:64 (a) Calculate the regression coefficients for the effects of x1 and x2 on y. Explain what these coefficients mean in plain English. (b) Calculate the standardized regression coefficients for the effects of x1 and x2 on y. Explain what these coefficients mean in plain English.

(c) Which one of the variables has the largest effect on prison violence? Explain why.