A researcher conducts a one-way ANOVA test on four groups. The level of significance is set to alpha = .05. Which of the following is the null hypothesis for the test?

	A.	There is a difference among the means of the groups; the means of the four groups are not equal.
	B.	One of the means of the groups is significantly greater than the means of the other three groups.
	C.	One of the means of the groups is significantly less than the means of the other three groups.
	D.	There is no difference among the means of the four groups; the means of the four groups are equal.