An educational psychologist is examining response times to an on-screen stimulus.The researcher believes there might be a weak effect from age, but expects a more pronounced effect for different color contrasts.She decides to examine a black on white (B/W) combination compared to 2 alternatives:red on white (R/W) and yellow on blue (Y/B).Here is the data for response times (in milliseconds):

Color SchemeB/WR/WY/BAge16-1744

17

21

8

32

24

20

2135

45

21

22

26

24

9

519

7

33

23

8

28

19

1318-1947

15

37

39

19

35

36

1723

32

15

11

24

16

13

1924

46

32

29

32

24

37

3720-2117

26

22

26

15

23

20

3841

26

19

29

29

20

31

2740

37

27

44

29

44

18

41

Using MS Excel, conduct a 2-way ANOVA with

=

0.05

=0.05

.Fill in the summary table.

The last column in the table below is read as, "Partial Eta-squared "and is a concept that wasNOTcovered in the lectures. Partial

²is used when there is a chance the data is not independent (click here to read more if interested) Computing the values for "Partial

²" is not difficult. Simply divide SS_effectby the sum of SS_effectand SS_error. For example, Partial

²(A) = SS_A/(SS_A+ SS_error)

P-values should be accurate to 4 decimal places and all other values accurate to 3 decimal places.

SourceSSdfMSF-ratioP-valuePartial

2

2

Age (A

A

)2Color (B

B

)2Interaction(

A

B

)

(AB)

4Error63

Provide the conclusions for this 2-way ANOVA.

What is the conclusion regarding the main effect for age (A

A

or rows):

• There appears to be an effect due to age.
• There is not enough evidence to reject the assumption that the marginal means across age groups are equal.

Correct

What is the conclusion regarding the main effect for color (B

B

or columns):

• There appears to be an effect due to color.
• There is not enough evidence to reject the assumption that the marginal means across color groups are equal.

Correct

What is the conclusion regarding an interaction effect between age and color (A

B

AB

):

• There appears to be an interaction effect between age and color.
• There is not enough evidence to reject the assumption of a lack of an interaction.