History of IQ tests
The concept of intelligence quotient (IQ) test was first introduced in 1912 by German psychologist and philosopher William Lewis Stern. First IQ-tests appeared in 1916. Interest to the IQ level has since increased dramatically which resulted in creation of lots of different IQ-tests. All IQ tests are based on logical tasks of different level of complexity. The IQ tests do not have common standard though, and at present you can find lots of such tests both in reading matter and on the internet. But the majority of these tests does not really determine your actual IQ-level. Many tests are created by modern magazines and internet publications that are far from true psychology.Eysenck test is a representative of a true IQ test. This test includes tasks of different type; these may be graphic tasks, calculation tasks, and combinatorics-related tasks. There are also Cettell test, Wechsler test, and some other tests for determination of IQ level.
Average test result is IQ-level of 100 points. This is about 50% of population, 25% is below 100 points and 25% is over 100 points respectively.
Interesting facts have been discovered during the history of existence of IQ-tests. For example, there was discovered relation between IQ-level of residents of a country and its GDP. The higher the IQ-level is the greater GDP of the country is. There was found relation between person's welfare and his/her IQ-level. People with higher IQ-level are usually better off irrespective of their occupation and eductaion.
By the way, result of IQ test depends on education of a person; for instance results of IQ tests of masters of science are higher than those of people without any higher education. But it is more likely that correlation here is inverse since it is quite improbable that a person with low IQ-level can become a master of science.
IQ test result also depends on training; it was found out that people, who have already taken IQ-test in the past get better results during their next tries.