What methods did we employ in this experiment?

On each trial you rated the happiness evoked by an image of abstract art. There were no right or wrong answers; we were just interested in your interpretation of the art. You made your judgments under three different conditions. One condition was a normal condition, but the other two conditions might have seemed odd. In one condition you were asked to place (or pretend to place) a pen or pencil between your teeth. This is a special condition because the act of holding a pen in your teeth utilizes facial muscles in a way that is similar to when you smile. The experiment is investigating whether making a smiling-type face influences your judgments of happiness in abstract art. A second condition is a kind of control condition where you held (or pretended to hold) a pen or pencil in your lips. This condition is just as odd as the teeth condition, but does not utilize muscles involved in smiling.

The dependent variable is the happiness rating, with 0 indicating the piece of art does not evoke happiness at all and 100 indicating very much happiness. We will use a one-way analysis of variance (ANOVA) to explore whether the happiness ratings are equal or different across the three conditions.

What do we predict participants will do? Why?

The null hypothesis is that the population mean happiness rating is the same for all three conditions:

H0: No pen = Teeth = Lips,

while the alternative hypothesis is that at least one of the means differs from the others

Ha: i j for some i,j.

If the effect exists, you will reject the null hypothesis, and the mean for the pen in teeth condition will be larger than the other means.

Mean happiness for art with no pen:

58

Mean happiness for art with the pen in your teeth:

47.09

Mean happiness for art with the pen in your lips:

55.09

Check answer

Variance of the means:

Mean Squared Between (MSB) variance:

Variance of happiness for art with no pen:

Variance of happiness for art with the pen in your teeth:

Variance of happiness for art with the pen in your lips:

Mean Squared Error (MSE) variance:

F value:

dfnumerator:

dfdenominator:

p-value:

Do you reject the null hypothesis?:

No

Trial Condition Happiness rating

1 No pen 39.0

2 No pen 60.0

3 No pen 5.0

4 No pen 55.0

5 No pen 18.0

6 No pen 75.0

7 No pen 93.0

8 No pen 61.0

9 No pen 61.0

10 No pen 85.0

11 No pen 86.0

12 Pen in teeth 26.0

13 Pen in teeth 35.0

14 Pen in teeth 55.0

15 Pen in teeth 21.0

16 Pen in teeth 35.0

17 Pen in teeth 60.0

18 Pen in teeth 43.0

19 Pen in teeth 64.0

20 Pen in teeth 86.0

21 Pen in teeth 75.0

22 Pen in teeth 18.0

23 Pen in lips 54.0

24 Pen in lips 59.0

25 Pen in lips 75.0

26 Pen in lips 40.0

27 Pen in lips 9.0

28 Pen in lips 86.0

29 Pen in lips 98.0

30 Pen in lips 65.0

31 Pen in lips 56.0

32 Pen in lips 4.0

33 Pen in lips 60.0