Statistics of Cooijmans Intelligence Test - Form 3

Preliminary norms

Scores on Cooijmans Intelligence Test - Form 3

Contents type: Verbal, numerical, spatial.   Period: 2009-present

• n: 30
• Median: 43.5
• Quartile deviation: 7.5
• Range: 51
• Maximum possible: 78
• Male median: 43.0 (n = 29)
• Female median: 57.0 (n = 1)
• Hardness: 0.44
• Resolution: 0.42

Correlation of Cooijmans Intelligence Test - Form 3 with other tests by Paul Cooijmans

Weighted average of correlations: 0.683

Conservatively estimated minimum g loading: 0.83

Ranking in above table is based on the unrounded correlations. All available data is present in this table, no tests are left out except for those with less than 4 score pairs. All known pairs are used to obtain the true, honest statistics; correlations have not been artificially inflated by leaving out ceiling scores, outliers or other anomalies.

Correlation of Cooijmans Intelligence Test - Form 3 with tests by others

Weighted average of correlations: 0.629

Ranking in above table is based on the unrounded correlations. All available data is present in this table, no tests are left out except for those with less than 4 score pairs. All known pairs are used to obtain the true, honest statistics; correlations have not been artificially inflated by leaving out ceiling scores, outliers or other anomalies.

Please be aware that correlations with these external tests are in most cases affected (depressed, typically) by one or more of the following: 1) Little overlap with the object test because of the much lower ceilings and inherent ceiling effects of the tests used in regular psychology; 2) Candidates reporting scores selectively, for instance only the higher ones while withholding lower ones; 3) Candidates reporting, or having been reported by psychometricians, incorrect scores.

Estimated loadings of Cooijmans Intelligence Test - Form 3 on particular item types

These are estimated g factor loadings, but against homogeneous tests containing only particular item types, as opposed to non-compound heterogeneous tests. Although tending to surprise the lay person, it is not uncommon for tests to have high loadings on item types they do not actually contain themselves. Such loadings reflect the empirical fact that most tests for mental abilities measure primarily g, regardless of their contents; that the major part of test score variance is caused by g, and only a minor part by factors germane to particular item types. It is of key importance to understand that this is a fact of nature, a natural phenomenon, and not something that was built into the tests by the test constructors.

There is no overlap between the categories in this table as a result of leaving out compound tests.

Balanced g loading = 0.82

National medians for Cooijmans Intelligence Test - Form 3

For reasons of privacy, only countries with 2 or more candidates are included in this table. Ranking is based on the medians, and then alphabetic.

Correlation with national I.Q.s of Cooijmans Intelligence Test - Form 3

Correlation of this test with national average I.Q.s published by Lynn and Vanhanen:

• r = 0.42 (n = 30)

Estimated g factor loadings Upward and Downward of specific scores

In parentheses the number of score pairs on which that estimated g factor loading is based. The Upward and Downward values are calculated including the pertinent score itself. It is normal that g factor loadings go down when the range is restricted like this, but careful study of the Upward and Downward columns may reveal possible scores below or above which the test loses validity altogether.

Reliability

• Split-half = 0.98
• Cronbach's alpha = 0.93

Error

• Standard error = 3.2 raw score points
• Quartile error = 2.0 raw score points
• Range of error = 13.4 raw score points

Scores by age

Scores by year taken

r_{year taken × median score} = 1.00 (n = 30)

Robustness and overall test quality

• Robustness by chronological rank = 0.79
• Robustness by month = 0.80
• Quality = 0.76

Item analysis

Item statistics are not published as that would help future candidates. To detect bad items, answers and comments from candidates are studied, as well as, for each problem, the correlation with total score and the proportion of candidates getting it wrong (hardness of the item). Possible bad items are removed or revised, resulting in a revised version of the test.

Correlations of sections with total score

Correlations between sections

Section histograms

Prop. = proportion of candidates outscored in this section.

Verbal

Numerical

Spatial