This question is meant to direct you to the important points from the relevant section of the textbook.  First, it is important to note that you will never need to use a table to locate a critical value for the F-ratio.  However, even though we always use computers to help us with the calculations, there are times when we need to locate additional information about results.  One common place for this is with SPSS and the ANOVA output.

The output for SPSS defaults to 3 decimal places for the significance (the p-value).  But, there are times when you need more accuracy.  In this case, we can take the F-ratio from the output and plug it into Excel.  Here is an ANOVA summary table to demonstrate how to do this:

	SS	df	MS	F-ratio	p-value
Between	473.76	2	236.88	13.16	0.000
Within	324	18	18
TOTAL	797.76	20

Remember, this does not mean the p-value is zero.  It means the p-value is less than 0.0005 (else it would have rounded up to a 3 decimal number.)  We can enter the F-ratio into Excel to obtain a more exact p-value.  The function we need to use is =FDIST(13.16,2,18) The first value is the F-ratio, the next value is the between samples degrees of freedom, and the third value is the within samples degrees of freedom.  If you enter this, you should obtain the value 0.00030.  (Remember, in SPSS output, you can double-click on the table then double-click on the desired value to obtain more than 3 decimal places.)

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Using Excel, find the probability of obtaining an F-ratio of $\displaystyle {F}={5.86}$ or larger with $\displaystyle {d}{f}={2},{18}$.  Report your answer accurate to at least 4 decimal places.

p-value =

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Remember, if you are reporting in a journal article a p-value like that obtained from the table above, DO NOT write $\displaystyle {p}={.000}$.  Instead, it is better to write $\displaystyle {p}<{.001}$ or even $\displaystyle {p}<{.0005}$.  (Technically, the p-value can never equal zero.)