IQ Test Manual

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Introduction

This test was designed by FunEducation, Inc. around 1998. It was refined slightly by William McConochie, Ph.D., a psychologist who works in partnership with FunEducation. Primarily, Dr. McConochie's contribution is the scoring system, statistical analysis and manual write-up. The test was designed as a brief intelligence test for administration over the Internet.

The test consists of 42 items in four content areas: Quantitative, Spatial, Words and Fill in the Blank. Three of the four content areas are "verbal", one "spatial".

Basic Statistical Properties

The test was administered to 90,000 persons over the Internet over several years. Initial norming was based on smaller samples. Detailed statistical properties were computed in September of 2007 for 65,000 of the 90,000 (the smaller size dictated by computer disk storage limits).

This sample included 44 percent males, 56 percent females. Scores for males and females were generally equal. The greatest difference was a slight advantage for males in the 12 spatial test items (.15**), consistent with other research that shows a slight advantage for males in this area of intelligence. The total score advantage for males was also significant but slight (.09**). Therefore, separate norms for males and females are not used.

Norms are based on each age year from ages 7 through 29 and for 10 or 5-year age clusters thereafter. Mean total raw scores rose in a steady arc from 22.4 for 7-year-olds to 28.7 for 25-year-olds and then remained level through age 60. They gradually declined thereafter to 24.0 for folks 85 and up.

Reliability Data

The Kuder-Richardson-21 reliability coefficients for a sample of ages are as follow:

Age Sample size KR-21 reliability coefficient
10 297 .78
20 2270 .74
30 1696 .72
40 1111 .78
50 750 .76
60 286 .78
70 63 .84
80 23 .87
90 16 .96

Thus, the test has modest reliability. Longer tests have higher reliability. For example, the Kids Verbal I.Q. test and the Spatial I.Q. Test authored by Dr. McConochie and normed over the Internet via FunEducation.com both have approximately 200 items over 5 test sections and have total score reliabilities of .95. Thus, persons can take the Free IQ Test for an initial estimate of their intelligence and one or both of the two longer tests for more reliable and more detailed scores.

Validity

The test is assumed to have content validity because the item content is typical of intelligence test content and the section scores all correlate in typical fashion with each other, with the total score and with other variables as expected:

Total I.Q. Quantitative Spatial Word Fill in Blank Age Education Gender (+ = male)
Total 1.00 .81** .82** .74** .81** .08** .19** .09**
Quant .81** 1.00 .53** .44** .56** .14** .19** .08**
Spatial .82** .53** 1.00 .46** .57** .00 .14** .15**
Word .74** .44** .46** 1.00 .47** .06** .11** .01*
Fill in .81** .56** .57** .47** 1.00 .05** .15** .07**
Age .08** .14** .00 .06** .05** 1.00 .35** .09**
Ed .19** .19** .14** .11** .15** .35** 1.00 -.07**
Gender .09** .08** .15** .01* .07** 0.09** -.07** 1.00

Summary

The Free IQ Test is a brief modestly reliable measure of general intelligence normed on large samples of persons from age 7 to 90. It provides an Internet product to introduce persons to intelligence testing.

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