Statistical Power - People.stat.sfu.ca

More documents

Recommendations

Info

• Effect: “Minimum response size that is considered biologically significant.”! • Statistical and biological significance are different.! • Biologically trivial differences may be statistically significant with large sample sizes and high power.! • Biologically important differences may not be statistically significant is power is low.! Background
!Effect: magnitude of response, original units! increase in fish concentration, 20 fish/m 2 ! !Effect size: standardized effect, percentage! if sd = 50 fish/m 2 , effect size = 20/50 = 0.4 = 40! !Effect size (alternate form): pct. difference from mean value! if mean = 60 fish/m 2 , 72 fish/m 2 = 20% increase! if mean = 60 fish/m 2 , 45 fish/m 2 = 25% decrease ! !Power to detect large effects is always greater  than power to detect small effects.! Background
Page 1 and 2: STATISTICAL POWER ANALYSIS IN WILDL
Page 3: !Interrelated components: target po
Page 7 and 8: • Set a meaningful effect size,
Page 9 and 10: Typical constraints:! • Maximum n
Page 11 and 12: • Change to crossover (paired) de
Page 13 and 14: Power is calculated using sample si
Page 15 and 16: Confidence Intervals and Power
Page 17 and 18: Points To Remember:! • Hypothesis

Statistical Power - People.stat.sfu.ca

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?