# Can you compare P-values?

C

## Can you compare P-values?

In your particular case there is absolutely no doubt that you can directly compare the p-values. If the sample size is fixed (n=1000), then p-values are monotonically related to t-values, which are in turn monotonically related to the effect size as measured by Cohen’s d. Specifically, d=2t/√n.

## What do p values tell us?

The p-value, or probability value, tells you how likely it is that your data could have occurred under the null hypothesis. The p-value tells you how often you would expect to see a test statistic as extreme or more extreme than the one calculated by your statistical test if the null hypothesis of that test was true.

Can P values be zero?

In theory, it’s possible to get a p-value of precisely zero in any statistical test, if the observation is simply impossible under the null hypothesis. In practice, this is extremely rare.

### What does P value mean in regression?

The p-value for each term tests the null hypothesis that the coefficient is equal to zero (no effect). A low p-value (< 0.05) indicates that you can reject the null hypothesis. Typically, you use the coefficient p-values to determine which terms to keep in the regression model.

### When P value is less than alpha?

If your p-value is less than your selected alpha level (typically 0.05), you reject the null hypothesis in favor of the alternative hypothesis. If the p-value is above your alpha value, you fail to reject the null hypothesis.

Is P-value same as Alpha?

Alpha sets the standard for how extreme the data must be before we can reject the null hypothesis. The p-value indicates how extreme the data are.

## Is 0.004 statistically significant?

In other words, the lower the p-value, the less compatible the data is to the null hypothesis (i.e. despite both being significant, p = 0.04 is a weaker significance value than p = 0.004 and therefore we would be more confident that the results are ‘true’ with p = 0.004), If we are confident that all assumptions were …

## Why is the P-value important?

The p-value is the probability that the null hypothesis is true. A low p-value shows that the effect is large or that the result is of major theoretical, clinical or practical importance. A non-significant result, leading us not to reject the null hypothesis, is evidence that the null hypothesis is true.

How do you report P values?

How should P values be reported?

1. P is always italicized and capitalized.
2. Do not use 0 before the decimal point for statistical values P, alpha, and beta because they cannot equal 1, in other words, write P<.001 instead of P<0.001.
3. The actual P value* should be expressed (P=.

### Is P 02 statistically significant?

For example, a p-value of . 02 means that, assuming that the treatment has no effect, and given the sample size, an effect as large as the observed effect would be seen in only 2% of studies. 05, then a p-value of . 05 or less is required to reject the null hypothesis and establish statistical significance.

### Are P values reliable?

P values (and confidence intervals, for that matter) do not account for the likelihood of the hypothesis being tested and cannot distinguish “true” from “false” results. They are purely data-based.