Table 1. Descriptive statistics of the WAIS-R subscales and self-rated mathematical skill.

Intelligence tests	Range	Mean	Median	Std. dev.
Arithmetic	0–19	10.94	11	3.37
Self-rated math skill	0–10	5.47	6	1.89
Digit span forward	0–14	7.88	8	1.83
Digit span backward	0–14	7.18	7	1.82
Similarities	0–28	19.61	20	3.09

Note. “Std. dev.” stands for “standard deviation”.