Welcome to Practical Stats
Statistical training and consulting for the environmental sciences and natural resources. From Singapore to South Dakota, our courses have enabled scientists to build better regression models, test for trends, see multivariate patterns, and correctly interpret nondetect (censored) data.
To train scientists in air, water, soil, and biological sciences to make sense of your data.
We provide online on-demand courses in Environmental Statistics. See our Training Page
for course details.
The 2020 version of the classic textbook Statistical Methods in Water Resources
is now available for download. See the link on our Books page
To be notified of our free semi-monthly webinars, sign up on our News page
and we'll send you an opt-in link to receive notices. Just Out -- How Many Observations Are Censored Data Worth?
Now on our Videos Page
as VID #5.
Your dataset has 30 observations, 12 of which are nondetects. How many equivalent observations do you have for the information content possessed in these data? Is it more than just 30 - 12 = 18 detected observations? Other questions that will be answered include:
* Is it true that "nondetects don't tell you much, you might as well drop them from the dataset"?
* Is there a limit of percent nondetects above which it is no longer worth doing statistics (over the years I've heard 20%, 50%, or more)?
* If the detection limit of an observation is (equal to; two times; more??) the highest detected value can I just throw that observation out?
See our Webinars Page
for details on past webinars available for viewing. Our Videos page has less-technical, general interest videos. Recordings of more technical webinars are available on our Online Training Center
as "free courses".
We've provided statistical training for the environmental sciences and natural resources since 1990 in the United States, Europe, Asia and the Middle East. See our credentials page
. We clearly communicate information to the working scientist. We make statistics current, accurate, and practical.
There are no advertisements.
Graphs only display the graphic, with no hidden functions.
If you send us email using our Contact Us page, we will respond to your email, which requires us to save your email address. Your email address is never provided to any other party or person.
If you send us email requesting an answer, you may receive occasional emails from us announcing information on environmental statistics (no more than 3 per year, usually less). In your Contact Us email you may request that we do not add you to our occasional information list, and your email address will not be saved — but you will not get useful information from us on environmental statistics.
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