Posted: May 26, 2008, 7:49 AM CST
rusty_knight wrote:Thank you but have me confused:
percentiles:
95% means you have scored 95 out of 100
95 percentile means you have scored better than 95% of the 'population'
the highest percentile are those with the highest IQ because they must have higher IQ's than the rest of the population.
percentage v. percentile - there is a large difference in what the two words mean..........
I'd rather have a lower IQ and be more successful at finding somebody wonderful to share the rest of my life with!
Some info on the scoring:
IQ stands for intelligence quotient. Supposedly, it is a score that tells one how “bright” a person is compared to other people. The average IQ is by definition 100; scores above 100 indicate a higher than average IQ and scores below 100 indicate a lower that average IQ. Theoretically, scores can range any amount below or above 100, but in practice they do not meaningfully go much below 50 or above 150.
Half of the population have IQ’s of between 90 and 110, while 25% have higher IQ’s and 25% have lower IQ’s:
Descriptive Classifications of Intelligence Quotients
IQ Description % of Population
130+ Very superior 2.2%
120-129 Superior 6.7%
110-119 High average 16.1%
90-109 Average 50%
80-89 Low average 16.1%
70-79 Borderline 6.7%
Below 70 Extremely low 2.2%
Apparently, the IQ gives a good indication of the occupational group that a person will end up in, though not of course the specific occupation. In their book, Know Your Child’s IQ, Glen Wilson and Diana Grylls outline occupations typical of various IQ levels:
140 Top Civil Servants; Professors and Research Scientists.
130 Physicians and Surgeons; Lawyers; Engineers (Civil and mechanical)
120 School Teachers; Pharmacists; Accountants; Nurses; Stenographers; Managers.
110 Foremen; Clerks; Telephone Operators; Salesmen; Policemen; Electricians.
100+ Machine Operators; Shopkeepers; Butchers; Welders; Sheet Metal Workers.
100- Warehousemen; Carpenters; Cooks and Bakers; Small Farmers; Truck and Van Drivers.
90 Laborers; Gardeners; Upholsterers; Farmhands; Miners; Factory Packers and Sorters.
IQ Expressed in Percentiles
IQ is often expressed in percentiles, which is not the same as percentage scores, and a common reason for the misunderstanding of IQ test scores. Percentage refers to the number of items which a person answers correctly compared to the total number of items presented. If a person answers 25 questions correctly on a 50 question test he would earn a percentage score of 50. If he answers 40 questions on the same test his percentage score would be 80. Percentile, however, refers to the number of other test takers’ scores that an individual’s score equals or exceeds. If a person answered 25 questions and did better than 50% of the persons taking the test he would score at the 50th percentile. However, if he answered 40 questions on the 50 item test and everyone else answered more than he did, he would fall at a very low percentile — even though he answered 80% of the questions correctly.
On most standardized tests, an IQ of 100 is at the 50th percentile. Most of our IQ tests are standardized with a mean score of 100 and a standard deviation of 15. What that means is that the following IQ scores will be roughly equivalent to the following percentiles:
IQ Percentile
65 01
70 02
75 05
80 09
85 16
90 25
95 37
100 50
105 63
110 75
115 84
120 91
125 95
130 98
135 99
An IQ of 120 therefore implies that the testee is brighter than about 91% of the population, while 130 puts a person ahead of 98% of people. A person with an IQ of 80 is brighter than only 9% of people, and only a few score less than 60.