Many statistical analyses involve the comparison of two treatments, procedures or subgroups of subjects. The numerical value summarizing the difference of interest is called the effect.
In other study designs the effect may be
a. Odds ratio (OR): H0 : OR=1
b. Relative risk (RR): H0 : RR=1
c. Risk Difference (RD): H0 : RD=0
d. Difference between means:H0 : Difference = 0
e. Correlation Coefficient : H0 : CC=0
Note that usually, the null hypothesis H0 states that there is no effect and the alternative hypothesis that there is an effect.
In other study designs the effect may be
a. Odds ratio (OR): H0 : OR=1
b. Relative risk (RR): H0 : RR=1
c. Risk Difference (RD): H0 : RD=0
d. Difference between means:H0 : Difference = 0
e. Correlation Coefficient : H0 : CC=0
Note that usually, the null hypothesis H0 states that there is no effect and the alternative hypothesis that there is an effect.
