Why Are P-values Uniformly Distributed in Hypothesis Testing?

  • Context: Undergrad 
  • Thread starter Thread starter alan2
  • Start date Start date
  • Tags Tags
    Distributed
Click For Summary
SUMMARY

P-values in hypothesis testing are uniformly distributed under the null hypothesis, particularly in continuous distributions. When generating p-values, one can create a uniform random number and apply the inverse cumulative distribution function (CDF) of the null distribution to obtain a p-value. This method holds true for left tail tests, where the p-value corresponds to the CDF evaluated at the test statistic. However, this uniformity may not apply to tests with discrete distributions or different acceptance/rejection regions.

PREREQUISITES
  • Understanding of hypothesis testing concepts
  • Familiarity with cumulative distribution functions (CDF)
  • Knowledge of test statistics and their distributions
  • Basic principles of random number generation
NEXT STEPS
  • Study the properties of p-values in hypothesis testing
  • Learn about the inverse CDF and its applications
  • Explore the differences between continuous and discrete distributions in hypothesis testing
  • Investigate acceptance and rejection regions in various statistical tests
USEFUL FOR

Statisticians, data analysts, social scientists, and anyone involved in hypothesis testing and statistical inference will benefit from this discussion.

alan2
Messages
324
Reaction score
56
Help. I need an intuitive, non-mathematical explanation of why p-values from hypothesis testing are uniformly distributed. I was talking to a social scientist and got a blank stare. I couldn't come up with anything except the proof. Thanks.
 
Physics news on Phys.org
alan2 said:
Help. I need an intuitive, non-mathematical explanation of why p-values from hypothesis testing are uniformly distributed. I was talking to a social scientist and got a blank stare. I couldn't come up with anything except the proof. Thanks.
If you wanted to generate random numbers from whatever the null distribution is, you would first generate a uniform random number and then apply the inverse cdf of the null distribution to get a random value. That value would be a (one-sided) p-value.
 
alan2 said:
Help. I need an intuitive, non-mathematical explanation of why p-values from hypothesis testing are uniformly distributed.

That won't be true if the the test statistic has a discrete distribution.
tnich said:
If you wanted to generate random numbers from whatever the null distribution is, you would first generate a uniform random number and then apply the inverse cdf of the null distribution to get a random value. That value would be a (one-sided) p-value.

That value would be a value ##t_0## of the test statistic. The p-value corresponding to ##t_0## would be (for a left tail test) the cdf evaluated at ##t_0## so you get back the original random number that you chose from a uniform distribution.

It looks like we're ok for a left tail test from a continuous distribution. Are things really going to work out for other types of acceptance/rejection regions?
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 3 ·
Replies
3
Views
15K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 24 ·
Replies
24
Views
4K
Replies
3
Views
12K
  • · Replies 21 ·
Replies
21
Views
4K
  • · Replies 17 ·
Replies
17
Views
3K
  • · Replies 4 ·
Replies
4
Views
1K