W-87 statistics

Introduction

These are statistics based on the W-87 scores reported by test candidates.

Scores on W-87 (I.S.P.E.) as of 5 July 2022

• n: 33
• Median: 152.0
• Quartile deviation: 3.0
• Range: 40
• Male median: 151.0 (n = 31)
• Female median: 154.5 (n = 2)
• Resolution: 0.35 (0.50 if half points are frequently given)

Correlation of W-87 (I.S.P.E.) with other mental ability tests

Weighted average of correlations: 0.108 (N = 154, weighted sum = 16.56)

Conservatively estimated minimum g loading: 0.33

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, including possible floor/ceiling scores or outliers.

Estimated loadings of W-87 (I.S.P.E.) 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.

N = 106

Compound tests have been left out of this table to avoid overlap.

Balanced g loading = 0.25

National medians for W-87 (I.S.P.E.)

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 W-87 (I.S.P.E.)

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

• r = 0.21 (n = 29)

Correlation of W-87 (I.S.P.E.) with personal details

Estimated g factor loadings upward and downward of particular scores

In parentheses the number of score pairs on which that estimated g factor loading is based. The goal of this is to verify the hypothesis that g becomes less important, accounts for a smaller proportion of the variance, at higher I.Q. levels. The mere fact of restricting the range like this also depresses the g loading compared to computing it over the test's full range, so it would be normal for both values to be lower than the test's full-range g loading.

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