IQ tests are norm-referenced tests (NRTs) based on what is basically a scientific sample.The test is first administered to a norm group intended to be representative of the population that will eventually take the test, and then their raw scores are converted into a scale so that an IQ score of 100 is in the middle.
On most modern IQ tests, the scale is arranged so that 95% of the scores spread out across a range of 70 to 130, with 66% falling within 85-115.
In simpler terms, when taking an IQ test, you’re not being ranked against the test based on percent of questions answered correctly like any regular school test.
Instead, you’re being ranked against other test-takers, or a sample group thereof, on a weighted scale.
If the vast majority of IQ scores from a certain test come in around the 125-134 range, as they appear to on this and several other online tests I’ve seen over the years, the test is inherently broken and not really showing IQ scores at all.
But how is it possible that 100 is always the average for IQ tests?