Why does IQ have a truncated normal distribution?

Does IQ have a normal distribution?

A graph of intelligence quotient (IQ), a measure of human intelligence, is an example of normal distribution, in which the most frequent scores are clustered near the center. The mean score is 100.

What is the distribution of IQs?

About 2% of the population has an IQ score lower than 69. Such a low IQ score often is hard to measure using a regular intelligence test.
IQ score ranges.

IQ scale Interpretation of IQ score % of population
90-110 Average intelligence 51.6%
80-89 Below average intelligence 15.7%
70-79 Cognitively impaired 6.4%

Are IQ tests discrete or continuous?

discrete scores

IQ test scores don’t increment in decimals, but in whole numbers (e.g., 138, 140, 150 etc.). In other words, IQ tests only provide discrete scores [not continuous] (No body can get an IQ score of 115.568…).

What was Einstein’s IQ level?

The maximum IQ score assigned by the WAIS-IV, a commonly-used test today, is 160. A score of 135 or above puts a person in the 99th percentile of the population. News articles often put Einstein’s IQ at 160, though it’s unclear what that estimate is based upon.

What is the highest IQ ever recorded?

IQ 228

Marilyn vos Savant: IQ 228
When Marilyn vos Savant was 10 years old, an adult-level Stanford-Binet test revealed she had an IQ of 228, which later landed her a Guinness World Record until the company removed the category in 1990 because the numbers are considered inexact.

Are IQ tests biased?

According to some researchers, the “cultural specificity” of intelligence makes IQ tests biased towards the environments in which they were developed – namely white, Western society. This makes them potentially problematic in culturally diverse settings.

Is IQ an accurate measure of intelligence?

According to Weiten, “IQ tests are valid measures of the kind of intelligence necessary to do well in academic work. But if the purpose is to assess intelligence in a broader sense, the validity of IQ tests is questionable.” Some scientists have disputed the value of IQ as a measure of intelligence altogether.