Null hypothesis (3 of 4)
Despite the "null" in "null hypothesis," there are occasions when the parameter is not hypothesized to be 0. For instance, it is possible for the null hypothesis to be that the difference between population means is a particular value. Or, the null hypothesis could be that the mean SAT score in some population is 600. The null hypothesis would then be stated as: H0: μ = 600. although the null hypotheses discussed so far have all involved the testing of hypotheses about one or more population means, null hypotheses can involve any parameter. An experiment investigating the correlation between job satisfaction and performance on the job would test the null hypothesis that the population correlation (ρ) is 0. Symbolically, H0: ρ = 0.
Some possible null hypotheses are given below:
H0: μ=0
H0: μ=10
H0: μ1 - μ2 = 0
H0: π = .5
H0: π1 - π2 = 0
H0: μ1 = μ2 = μ3
H0: ρ1- ρ2= 0