Experimental PSY

Question

Randy found a perfect negative correlation among spouses in a weight loss program. The older spouse of each pair were assigned to Group C and the younger spouse of each pair were assigned to Group D. He found that for every unit of increase in weight for those in Group C, there was a decrease of 6 units in weight for those in Group D. Fill in the table. Refer to Video 2, Slide 9 (Correlation Examples).

Group C….. Group D…..

150 lbs 225 lbs

151 lbs

152 lbs

153 lbs

154 lbs

Answer 1

Hi Constance,

You have a slope of -6, which means that for every one unit increase in x (Group C weight here), there is a 6-unit decrease in y (Group D weight here). So: each individual value for group D drops by 6 lbs. Perfect negative correlation implies r = -1, which means the graph is a straight line downward and hits all points:

Group C Group D

150 lbs. 225 lbs.

151 lbs. 219 lbs.

152 lbs. 213 lbs. ....

and so on. I hope this helps.