An electrical engineer wants to compare the resistance of four types of wire made from different materials.Five wires of equal lengths and cross sectional areas are prepared for each of the four wire types.Each section of wire is randomly tested by sending a current through the wire and measuring the resistance.How many degrees of freedom does the treatment sum of squares have? How about the error sum of squares?
A)df-treatment = 4; df-error = 19
B)df-treatment = 3; df-error = 17
C)df-treatment = 3; df-error = 16
D)df-treatment = 4; df-error = 20
E)df-treatment = 3; df-error = 19

Question

Quizplus · Accepted Answer

The treatment sum of squares has 3 degrees of freedom because there are 4 types of wire and 1 degree of freedom is lost to the overall mean. The error sum of squares has 16 degrees of freedom because there are 5 wires of each type and 1 degree of freedom is lost to the mean of each type.

An Electrical Engineer Wants to Compare the Resistance of Four