The correct answer is D. Analysis of variance (ANOVA). To compare the means of three samples -- perhaps three experimental treatments -- we should use ANOVA Test.
ANOVA is a statistical test that is used to compare the means of two or more samples. It can be used to determine whether there is a significant difference between the means of the samples, and to identify which samples are significantly different from one another.
A pooled variance t-test is a statistical test that is used to compare the means of two samples, assuming that the variances of the two samples are equal. This test is not suitable for comparing the means of three or more samples.
A separate variance t-test is a statistical test that is used to compare the means of two samples, assuming that the variances of the two samples are not equal. This test is also not suitable for comparing the means of three or more samples.
A z-test of difference of means is a statistical test that is used to compare the means of two independent samples. It is not suitable for comparing the means of three or more samples.
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