How to handle conservativeness of Exact p-value?

Posted by Ashwini Joshi

Sep 18, 2017 7:38:45 AM

 

By Ashwini Joshi

For small sample data or rare events data, exact non-parametric tests perform better than asymptotic tests. But they come with the disadvantage of conservativeness. Many corrections have been suggested to reduce this conservativeness but none of them solve the problems entirely.  StatXact provides various methods of computing exact p-values. Depending upon the problem at...

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Topics: biostatistics, p value, StatXact, exact statistics, Small Sample Sparse Data, Exact Tests


Inference on Confidence Intervals for Adaptive Designs: The Latest Breed of Adaptive Clinical Trials

Posted by Esha Senchaudhuri

Sep 17, 2015 3:51:00 PM

Most people familiar with adaptive clinical trial designs are familiar with those statistical designs that reject the null hypothesis. These include now familiar designs like the promising zone design and the adaptive switch design

A newer breed of adaptive designs, however, aims to apply adaptation techniques to confidence intervals.

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Topics: Cyrus Mehta, Exact Tests, Adaptive Clinical Trials


StatXact 25th Anniversary: Reflections of a Pioneer

Posted by Professor Joan Hilton (Guest Author)

Apr 30, 2014 4:15:00 PM

For the second installment of our StatXact 25th Anniversary Retrospective Series, Professor Joan Hilton (UC San Francisco) reflects on her pioneering work on exact conditional inferences.

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Topics: StatXact, Cyrus Mehta, Exact Tests, Exact tests for categorical data, Webinar Slides


StatXact 25th Anniversary: A Horizon for the Stars

Posted by Esha Senchaudhuri

Apr 21, 2014 3:57:00 PM

The core methodological problem that would eventually spur the development of Cytel’s StatXact software was first posed by Harvard’s Marvin Zelen at a computational seminar in the late 1970s. Zelen, a distinguished professor of statistical sciences and head of the Department of Biostatistics at Harvard University, was also serving as the Director of the Dana Farber Cancer Institute.

The...

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Topics: StatXact, Nitin Patel, Cyrus Mehta, White Paper, Statistics Article full PDF, Oncology, Access to Paper PDF, Exact Tests, Marvin Zelen, Statistical Puzzles


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