Abstract
3 factors are considered to influence performance on mental tests: mental precision, mental speed, and intervention frequency, which is identified by an s skipping an item he considers too difficult. The number of items right is indicated by r, wrong by w, omitted by o and attempted by A. Mental precision indicates the proportion of r's out of items answered. Mental speed is expressed by A. The interesse, schoolvordingen en intelligentie test was administered to about 500 boys and 500 girls with a ca of 11-12 yr. The scores were analyzed with respect to the 3 factors in addition to verbal abilities and pictorial abilities. According to the data analyzed by kaiser's varimax criteria, the factors had high loadings in determining the variation. Abilities in verbal and pictorial areas were apparently unimportant in determining the variation. Mental precision and intervention frequency were independent. Mental speed had no correlation with mental precision and intervention frequency. Apparently time-limited tests should provide ample time limits.
