Question

A forensic psychologist tests the extent to which the age of a criminal (X) predicts the age of the victim () for nonviolent crimes. The psychologist uses the case files to record the age of five criminals and the age of the victim in those cases. The hypothetical data are listed in the following table Age of Criminal Age of Victim 25 20 25 25 29 16 (a) Compute the method of least squares to find the equation of the regression line. (Round your answers to three decimal places.) (b) Use the regression equation to determine the predicted age of a victim of a nonviolent crime when the criminal is 22 years old. (Round your answer to three decimal places.) years old

Answer 1

x: Age of criminal: Independent variable

y: Age of victim: Dependent variable

a) The regression equation is y = b*x + a

Here a is intercept and b is a slope.

b=-.ry _ nzy 2

	x	y	xy	x^2
	33	25	825	1089
	25	20	500	625
	29	25	725	841
	18	22	396	324
	13	16	208	169
Total	118	108	2654	3048

= 2654

ry

= 3048

= 23.6

= 21.6

n = 5

So the regression equation is

= 0.400*X + 12.167

b)

Criminal = X = 22

= 0.400*X + 12.167 = 0.400*22 + 12.167 = 20.960