To illustrate the logic of null hypothesis testing, consider Mehl and colleagues' investigation into whether men and women differ in talkativeness. Assuming the null hypothesis (that there is no difference in the population) was true, they evaluated the likelihood of finding their sample's small difference of $d = 0.06$. Finding this result fairly likely under the null hypothesis, they decided to retain the null hypothesis, concluding there was no evidence of a sex difference in the population.