If "half the population is below the average IQ", then is the average IQ really average?

I've half a mind to think about that.

Romany "If "half the population is below the average IQ", then is the average IQ really average?"

I suggest you go back and think about it some more.

If "half the population is below the average IQ", then is the average IQ really average?
Posted by Romany, Thursday, 20 March 2008 2:04:19 PM

I suggest you go back and think about it some more.
Posted by Col Rouge, Thursday, 20 March 2008 2:34:11 PM

How long do we have to wait to get the right answer?

If half the population is below the average and the other half is above the average, then the average is the half-way point between the two. But it assumes that the average has been defined first, without reference to the other half that might or might not be above the average. In fact you could have 90% below the average and the remaining 10% so high in IQ above the average that the average stays where it was when the discussion started.

Right-brain stuff, that.

HenryVIII You got it.

The “average”, in a normal distribution, will be exactly in the middle, with half the population above and half below average IQ.

However what you go on to describe would require a significant skew in the distribution curve (to the point of being bizarre).

Footnote my understanding to construct of the standard IQ test is: one standard deviation is predeterminde as 15 points on the scale with 100 being the mean.

Thus an IQ of 70 = (mean - 2 SD) and

An IQ of 130 = (mean + 2 SD)

Simply put, based on a normal distribution, 95.45% of the population will have an IQ between 70 and 130.

And 2.275% of the population will be over 130.

And 2.275% of the population will be under 70.

Hope that explains it folks (but it is still a scarey thought).