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


Wild Horses: How StatXact is helping conservation project in Mongolia

Posted by Cytel

Jul 7, 2016 10:30:00 AM

 

Why do we do what we do?  At Cytel we have always been driven to deliver benefits in the service of human health, and ultimately to bring new drugs to the patients who need them.  In the context of our work in statistical software, we have recently had the opportunity to support an important conservation project defined by a similar passion to make a difference.  

While our core focus has...

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Topics: StatXact, Statistical Programming, exact statistics, Simulations, biostatistics, non parametric analysis


3 Strategies to Combat Inferential Conservatism in Small Sample Sizes

Posted by Cytel

Jun 25, 2015 4:28:00 PM

When conducting a clinical trial with small or sparse data sets, statistical methods meant for large sample sizes may fail to obtain an accurate interpretation of data. This is where computationally challenging exact methods often come into play.

Exact methods, however, are inferentially conservative in the sense that due to small sample sizes, the actual Type 1 error rate is often smaller...

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Topics: Sample Size, Exact Inference, exact statistics, Small Sample Sparse Data


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