

 :: Tukey lambda PPCC Plot  Free Statistics Software (Calculator) :: 


All rights reserved. The noncommercial (academic) use of this software is free of charge. The only thing that is asked in return is to cite this software when results are used in publications.
This free online software (calculator) computes the Tukey lambda PPCC Plot that is used to identify whether a distribution is short or long tailed (only applies to symmetric distributions). In addition it can indicate several common distributions. Specifically,
 lambda = 1: distribution is approximately Cauchy
 lambda = 0: distribution is exactly logistic
 lambda = 0.14: distribution is approximately normal
 lambda = 0.5: distribution is Ushaped
 lambda = 1: distribution is exactly uniform

If the Tukey Lambda PPCC plot gives a maximum value near 0.14, we can reasonably conclude that the normal distribution is a good model for the data. If the maximum value is less than 0.14, a
longtailed distribution such as the double exponential or logistic would be a better choice. If the maximum value is near 1, this implies the selection of very longtailed distribution, such as the Cauchy. If the maximum value is greater than 0.14, this implies a shorttailed distribution such as the Beta or uniform.
source: NIST/SEMATECH eHandbook of Statistical Methods, http://www.itl.nist.gov/div898/handbook/, 20061003.
Enter (or paste) your data delimited by hard returns.
Source code of R module  

Cite this software as:  Wessa P., (2013), Tukey lambda PPCC Plot (v1.0.3) in Free Statistics Software (v1.2.1), Office for Research Development and Education, URL http://www.wessa.net/rwasp_tukeylambda.wasp/   The R code is based on :   NIST/SEMATECH eHandbook of Statistical Methods, http://www.itl.nist.gov/div898/handbook/, 20061003.              

To cite Wessa.net in publications use: Wessa, P. (2018), Free Statistics Software, Office for Research Development and Education, version 1.2.1, URL https://www.wessa.net/
© All rights reserved. Academic license for noncommercial use only.
The free use of the scientific content, services, and applications in this website is
granted for non commercial use only. In any case,
the source (url) should always be clearly displayed. Under no circumstances are
you allowed to reproduce, copy or redistribute the design, layout, or any
content of this website (for commercial use) including any materials contained
herein without the express written permission.
Information provided
on this web site is provided "AS IS" without warranty of any kind, either
express or implied, including, without limitation, warranties of
merchantability, fitness for a particular purpose, and noninfringement. We use reasonable efforts to include accurate and timely information
and periodically update the information, and software without notice. We
make no warranties or representations
as to the accuracy or completeness of such information (or software), and it assumes no
liability or responsibility for errors or omissions in the content of this web
site, or any software bugs in online applications. Your use of this web site is AT YOUR OWN RISK. Under no circumstances and
under no legal theory shall we be liable to you or any other
person for any direct, indirect, special, incidental, exemplary, or
consequential damages arising from your access to, or use of, this web site.
Software Version : 1.2.1 Algorithms & Software : Patrick Wessa, PhD Server : wessa.net
About  Comments, Feedback & Errors  Privacy Policy  Statistics Resources  Wessa.net Home






