Table 1 Factors that affect sample size calculations
Factor | Magnitude | Impact on identification of effect | Required sample size |
|---|---|---|---|
P value | Small | Stringent criterion; difficult to achieve 'significance' | Large |
| Â | Large | Relaxed criterion; 'significance' easier to attain | Small |
Power | Low | Identification unlikely | Small |
| Â | High | Identification more probable | Large |
Effect | Small | Difficult to identify | Large |
| Â | Large | Easy to identify | Small |