Re: cutting tails of samples

2002-01-31 Thread Jon Miller
Harold W Kerster wrote: Look at minitab's trimmed mean. It is a Tukey (I think) invention w/5% chopped from each end, leaving the central 90%. For the high variance, high skew, common world, a good approach. Oh, yeah, especially when setting reserves. Or calculating premiums. Those

Re: cutting tails of samples

2002-01-31 Thread kjetil halvorsen
Hola! But the original poster asked about trimming IN THE MARGINAL DISTRIBUTION with multivariate data --- and that is totally insane. If trimming should be used in regression settings , the residuals should be trimmed - as in Rousseuw and Leroy's LTS (least trimmed mean of squares), implemented

Re: cutting tails of samples

2002-01-30 Thread Harold W Kerster
Look at minitab's trimmed mean. It is a Tukey (I think) invention w/5% chopped from each end, leaving the central 90%. For the high variance, high skew, common world, a good approach. On Tue, 29 Jan 2002, Rich Ulrich wrote: On 17 Jan 2002 00:05:02 -0800, [EMAIL PROTECTED] (Hekon) wrote:

Re: cutting tails of samples

2002-01-30 Thread Dennis Roberts
here is an example from minitab ... in moore and mccabe's book intro. to practice of statistics ... 3rd edition ... they have an example of speed of light measurements ... with newcomb in his lab on the bank of the potomac ... bouncing light bursts off the base of the washington monument ...

Re: cutting tails of samples

2002-01-29 Thread Rich Ulrich
On 17 Jan 2002 00:05:02 -0800, [EMAIL PROTECTED] (Håkon) wrote: I have noticed a practice among some people dealing with enterprise data to cut the left and right tails off their samples (including census data) in both dependent and independent variables. The reason is that outliers tend to

cutting tails of samples

2002-01-17 Thread Håkon
I have noticed a practice among some people dealing with enterprise data to cut the left and right tails off their samples (including census data) in both dependent and independent variables. The reason is that outliers tend to be extreme. The effects can be stunning. How is this practice to be