[Joseline]

Originally Posted by Redway

Yeah, extreme cases tend to be pulled back towards the average. So if you get a very low score (70-) they'll add a lot of points and if you get a very high score (120/130+), they tend to subtract a lot of points. :/

It's entirely symmetrical for average scores based around 100 but it's a bit uneven before and after that.

Yeah, positive and negative skews and all that. Someone should come up with a transformations of the log-normal distribution to model the the CI size for scores above 100.

[Redway]

Originally Posted by Joseline

Yeah, positive and negative skews and all that. Someone should come up with a transformations of the log-normal distribution to model the the CI size for scores above 100.

Agree. Mind, scores marginally above 100 are nothing to write home about. You only really start hitting above average once you get to 115, though on some tests that's 110/111, is it not?