STATISTICAL TECHNIQUES AND TOOLS
ANALYSIS OF VARIANCE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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There are two df values for each F-test.
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df1 is for the variance in the numerator.
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df2 is for the variance in the denominator.
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F-ratio is always negative.
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Detailed explanation-1: -The F-distribution cannot take negative values, because it is a ratio of variances and variances are always non-negative numbers. The distribution represents the ratio between the variance between groups and the variance within groups.
Detailed explanation-2: -Characteristics of the F-ratio The numerator and denominator of the ratio measure exactly the same variance when the null hypothesis is true. Thus: when Ho is true, F is about 1.00. F-ratios are always positive, because the F-ratio is a ratio of two variances, and variances are always positive.
Detailed explanation-3: -The F-distribution is the sampling distribution of the ratio of the variances of two samples drawn from a normal population. It is used directly to test to see if two samples come from populations with the same variance.