Linked Questions

168 votes
5 answers
101k views

Why are p-values uniformly distributed under the null hypothesis?

Recently, I have found in a paper by Klammer, et al. a statement that p-values should be uniformly distributed. I believe the authors, but cannot understand why it is so. Klammer, A. A., Park, C. Y.,...
golobor's user avatar
  • 1,713
86 votes
10 answers
24k views

Regarding p-values, why 1% and 5%? Why not 6% or 10%?

Regarding p-values, I am wondering why $1$% and $5$% seem to be the gold standard for "statistical significance". Why not other values, like $6$% or $10$%? Is ...
Contango's user avatar
  • 1,489
96 votes
5 answers
36k views

When to use Fisher versus Neyman-Pearson framework?

I've been reading a lot lately about the differences between Fisher's method of hypothesis testing and the Neyman-Pearson school of thought. My question is, ignoring philosophical objections, when ...
Stijn's user avatar
  • 1,892
81 votes
4 answers
29k views

How should tiny $p$-values be reported? (and why does R put a minimum on 2.22e-16?)

For some tests in R, there is a lower limit on the p-value calculations of $2.22 \cdot 10^{-16}$. I'm not sure why it's this number, if there is a good reason for ...
paul's user avatar
  • 1,422
46 votes
4 answers
17k views

Are smaller p-values more convincing?

I've been reading up on $p$-values, type 1 error rates, significance levels, power calculations, effect sizes and the Fisher vs Neyman-Pearson debate. This has left me feeling a bit overwhelmed. I ...
Zenit's user avatar
  • 1,846
33 votes
3 answers
1k views

Accommodating entrenched views of p-values

Sometimes in reports I include a disclaimer about the p-values and other inferential statistics I've provided. I say that since the sample wasn't random, then such statistics would not strictly apply....
rolando2's user avatar
  • 12.8k
6 votes
4 answers
593 views

What is the information in an exact p-value?

Consider the following two statistical principles: 1) an exact test's $p$-value gives the exact frequency with which the observed random sample appears by chance, i.e., under a true null hypothesis; ...
virtuolie's user avatar
  • 642
6 votes
1 answer
4k views

What is an F test?

What is an F test and what does it show? Also what is an alpha, and how do I evaluate the p-value?
user3069564's user avatar
1 vote
2 answers
9k views

Interpret F-Value in ANOVA [duplicate]

When we conduct an ANOVA, we get F-Value and P-Value. If P-value if smaller than our alpha level of .05 for example, we reject our null hypothesis. What is the importance of F-Value that is obtained ...
user39531's user avatar
  • 627
3 votes
1 answer
5k views

Likert item as independent variable for ANOVA?

I am trying to analyze data based on a sample size of around 50 and would appreciate advice on which statistical test would be most appropriate. Participants, on a single questionnaire, were asked to ...
user49440's user avatar
1 vote
3 answers
2k views

Finding the level of significance of a sample

I have an exercise with the following information; $ 20\% $ of the set are youth, my sample of $ 139 $ persons have $ 39 $ youths. The exercise is to test if this sample is a representative sample of ...
oyvindym's user avatar
  • 111
1 vote
1 answer
137 views

Least Squares Fits to Experimental Data

My attempt at making sense of the problem: The problem provides us with the sum of squares (SS; I believe that's the $18.1$). We can use the SS along with the number of samples $(21)$ to get the ...
user avatar
1 vote
0 answers
26 views

Upsides of reporting a lower or upper bound vs. reporting the actual value [duplicate]

I often see research papers reporting lower or upper bounds. E.g.: Patients treated with the splint regained mobility significantly more quickly (p less than 0.001) and preferred the splint to the ...
Franck Dernoncourt's user avatar