Stats ch.13 review

What happens to the value of the F-ratio if the differences between treatments are increased? What happens to the F-ratio if variability inside the treatments is increased?

As differences between treatments increase, the F-ratio will increase. As variability within treatments increases, the F-ratio will decrease.

ANOVA is a statstical procedure that compares 2 or more treatment conditions for difference is variance. ( true or false?)

False. Although ANOVA uses variance in the computations, the purpose of the test is to evaluate differences in means between treatments.

If the SS for one treatment was increased what would happen to the size of the F-ratio? (increase or decrease?

If the SS were increased for one treatment, it would increase the size of variability within treatments. This would increase the MSw/in and would reduce the size of the F-ratio. ( inversly proportionate)

If the mean for a treatment is reduced closer to the other means, what would happen to the size of the F-ratio? (increase or decrease?

If the mean were changed lower, it would reduce the size of the mean differences ( all 3 means would be closer together). This would reduce the size of MSb/w and would reduce the size of the F-ratio. (proportionate)

In ANOVA, the total variability is partitioned into two parts. what are these two variability componenets called and how are they used in the F-ratio?

The two components are between-treatments variabilty and within-treatments variability. Between-treatments variance is the numerator of the F-ratio, and the within-treatments variance is the denominator.

In ANOVA, what value is expected on the average for the F-ratio when the null hypothesis is true?

When the null is true, the expected value for the F-ratio is 1.00 because the top and bottom of the ratio are both measuring the same varience.