Question 15.17

For Exercises 15.1 to 15.3, see pages 15-6 to 15-7; for 15.4 to 15.6, see page 15-10; for 15.7, see pages 15-12 to 15-13; for 15.8 to 15.10, see page 15-15; for 15.11, see page 15-16; for 15.12 and 15.13, see page 15-18; and for 15.14 to 15.16, see pages 15-20 to 15-21.

Question 15.17

15.17 Describing a two-way ANOVA.

A $4 \times 2$ ANOVA was run with six observations per cell.

Give the degrees of freedom for the $F$ statistic that is used to test for interaction in this analysis and the entries from Table E that correspond to this distribution.
Sketch a picture of this distribution with the information from Table E included.
The calculated value of the $F$ statistic is 2.68. What is the $P$ -value?
Would you expect a plot of the means to look parallel? Explain your answer.

15.17

(a) $DF = 3, 40.$ (c) $0.05 < P -value < 0.10.$

$P -value$	$F$
0.100	2.23
0.050	2.84
0.025	3.46
0.010	4.31
0.001	6.59

(d) The plot would be roughly parallel because the interaction is only marginally significant.