Effect sizes, P-values and confidence intervals

P-values come from testing theories using sample data.

You will routinely find P-values in the output of statistical software.

Finding a small P-value in the results of an analysis.

There is a renewed emphasis on reporting effect sizes, with the hope that this will encourage researchers to rely less on statistical significance.

Confidence intervals appear in reports of statistical analysis, academic papers and sometimes in mainstream media.

A confidence interval contains a range of values for the parameter of interest that are plausible, given the data.