Help with Matching

Twelve subjects volunteered for an experiment on memory. The independent variable is the length of time between the presentation of a word list and a test of the subject’s recall. There are three levels of this independent variable: 1 hour, 2 days and 6 weeks. Assign the following list of subjects to levels of the independent variable using randomization, matching on gender only, and matching on gender and IQ. Compare the gender and IQ breakdowns for these three methods. Which method produced the greatest equality of gender and IQ?

Name Gender IQ

Barb F 122
Bert M 115
Carly F 123
Joan F 135
Kelly F 110
Larry M 122
Mike M 125
Ned M 115
Theo M 131
Veronica F 101
Vivian F 115
Walter M 101