FIGURE 2.

The four principles of inference by intervals. (i) If the interval is completely contained in the null region, decide that the population value lies in the null region (accept the null region hypothesis); (ii) If the interval is completely outside the null region, decide that the population value lies outside the null region (reject the null region hypothesis); (iii) If the upper limit of the interval is below the minimal interesting value, decide against a theory postulating a positive difference (reject a directional theory); (iv) If the interval includes both null region and theoretically interesting values, the data are insensitive (suspend judgment).