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Differences between revisions 15 and 17 (spanning 2 versions)
 ⇤ ← Revision 15 as of 2008-02-13 10:51:59 → Size: 671 Editor: PeterWatson Comment: ← Revision 17 as of 2008-02-13 10:53:14 → ⇥ Size: 744 Editor: PeterWatson Comment: Deletions are marked like this. Additions are marked like this. Line 10: Line 10: \$\$2^text{-0.05}\$\$ln(2)^text{0.05}\$\$ \$\$2^text{-0.05}ln(2)^text{0.05}\$\$ Line 13: Line 13: (See [http://www.weibull.com/AccelTestWeb/weibull_distribution.htm here.]

# How do I produce random variables which follow a negatively skewed distribution?

Most distributions such as the exponential and log-Normal distributions are positively skewed with the mode of the distribution occurring for lower values.

The Weibull distribution is negatively skewed and may be generated [http://www.taygeta.com/random/weibull.xml using random variables which are uniform on the interval [0,1]]

The below produces an open ended negatively skewed weibull distribution with parameters, 2 and 20. It has a median of

\$\$2text{-0.05}ln(2)text{0.05}\$\$ = 0.95.

```compute wrv= (-(1/2)*(ln(1-rv.uniform(0,1))))**(0.05).
exe.```

None: FAQ/gamma (last edited 2013-03-08 10:17:36 by localhost)