What kind of kurtosis calculates Deducer?

[iurie...@gmail.com]

Kurtosis characterizes peakedness, where the normal distribution has a value of 3 and smaller values correspond to thinner tails (less peakedness). Some packages substract three (3) from the kurtosis, so that the normal distribution has a kurtosis of 0 (this is sometimes called "excess kurtosis". What kind of kurtosis calculates Deducer (menu Analysis>Descriptives)?

[Ian Fellows]

Deducer uses type two, the same as SAS/SPSS

G_2 = ((n+1) g_2 + 6) * (n-1) / ((n-2)(n-3))

ian

[iurie...@gmail.com]

Thank you!

So, in Deducer the normal distribution will have a kurtosis of 0?

Iurie

[Ian Fellows]

yes.

>kurtosis(rnorm(100000))
[1] -0.003919868