Question

In a market research study, members of a consumer test panel are asked to rate the visual appeal (on a 1 to 10 scale) of the texture of dashboard plastic trim in a mockup of a new fuel cell car. The manufacturer is testing four finish textures. Panelists are assigned randomly to evaluate each texture. The test results are shown below. Each cell shows the average rating by panelists who evaluated each texture. Research question: Is mean rating affected by age group and/or by surface type?

Mean Ratings of Dashboard Surface Texture
Age Group	Shiny	Satin	Pebbled	Pattern
Youth (under 21)	6.5	6.1	5.5	4.4
Adult (21 to 39)	5.3	5.9	6.5	5.7
Middle-Age (40 to 61)	4.6	5.1	6.8	5.2
Senior (62 and over)	3.4	4.7	6.2	4.6

(b) Fill in the missing data. (Round your SS values to 3 decimal places, F values to 2 decimal places, and other answers to 4 decimal places.)

   

Table of Means
	Mean	n	Std. Dev
Shiny
Satin
Pebbled
Pattern
Youth (Under 21)
Adult (21 to 39)
Middle-Age (40 to 61)
Senior (62 and over)
Total

ANOVA Table
Source	SS	df	MS	F	p-value
Rows (Age Group)
Columns (Surface)
Error
Total

Answer 1

SUMMARY	Count	Sum	Average	Variance
Youth(under 21)	4	22.5	5.625	0.835833
Adult	4	23.4	5.85	0.25
middle	4	21.7	5.425	0.909167
Senior	4	18.9	4.725	1.315833
Shiny	4	19.8	4.95	1.683333
Satin	4	21.8	5.45	0.436667
Pebbled	4	25	6.25	0.31
Pattern	4	19.9	4.975	0.349167

ANOVA
Source of Variation	SS	df	MS	F	P-value	F crit
Rows	2.836875	3	0.945625	1.547211	0.26859	3.862548
Columns	4.431875	3	1.477292	2.417112	0.133544	3.862548
Error	5.500625	9	0.611181
Total	12.76938	15