RafsHistogramDifferenceMeans

A randomisation distribution. It shows the distribution of all 184,756 differences between means for every possible way of choosing 10 observations from 20, based on the assumption that the pills are identical, so the mean of the distribution is zero. The vertical dashed lines mark 2.5% of the area in the lower tail and 2.5% in the upper tail. The red line marks the difference between means that was observed in the experiment. Because the red line lies between the dashed lines we can conclude that there is not strong evidence to say that the true difference is not zero.