Psychological Statistics 1 (PSYSTA1)

Arden and Plomin (2006) published a study reporting that IQ scores for boys are more variable than IQ scores for girls. A researcher would like to know if this same phenomenon applies to other measures of cognitive ability. A standard cognitive skills test is given to a sample of 
�
=
15
adolescent boys and a sample of 
�
=
15
adolescent girls, and resulted in the following scores.

Boys

Girls

9 5 3 9 7

6 5 4 6 7

5 2 4 8 8

6 4 7 6 8

7 4 9 7 3

5 7 8 6 5

Compute the mean, the variance, and the standard deviation for each group.

Is one group of scores noticeably more variable than the other?