244 Frequently Asked Questions In Quantitative Finance
Variance
1
3π^2 b^2.Laplace This distribution is unbounded below and above.
It has two parameters:a, location;b>0 scale. Its prob-
ability density function is given by
1
2 be−|x−a|
b.Errors in observations are usually either normal or
Laplace.Mean
a.
Variance
2 b^2.Laplace
00.020.040.060.080.10.120.140.160.18-4 -3 -2 -1 0 1 2 3 4a = 1b = 3