In: Statistics and Probability
A study was conducted to see how people reacted to certain facial expressions. A sample group of n=36n=36 was randomly divided into six groups. Each group was assigned to to view one picture of a person making a facial expression. Each group saw a different picture, and the different expressions were (1) Surprised (2) Nervous (3) Scared (4) Sad (5) Excited (6) Angry. After viewing the pictures, the subjects were asked to rank the degree of dominance they inferred from the facial expression they saw. (The scale ranged from -10 to 10) The data collected is summarized in the table below.
Surprised | Nervous | Scared | Sad | Excited | Angry |
0.20.2 | −1−1 | 1.81.8 | 00 | 1.31.3 | 0.50.5 |
−1−1 | 0.20.2 | 1.91.9 | 1.71.7 | 0.80.8 | −0.3−0.3 |
−0.7−0.7 | −2−2 | 0.70.7 | −1.3−1.3 | 0.60.6 | 1.21.2 |
0.90.9 | −1.4−1.4 | −2−2 | 0.40.4 | −2−2 | −0.8−0.8 |
0.40.4 | 1.11.1 | −0.3−0.3 | 0.20.2 | 1.61.6 | −1.1−1.1 |
00 | 1.71.7 | −0.0999999999999999−0.0999999999999999 | 1.41.4 | −0.0999999999999999−0.0999999999999999 | 1.11.1 |
Complete the following ANOVA table
Source | df | SS | MS | FF |
Expressions | ||||
Error | ||||
Total |
I input the data set in MS Excel and use the "Anova: Single Factor" option under Data > Data Analysis to carry out this one way Anova analysis and complete the following Anova table. The output is given below.
Anova: Single Factor | ||||||
SUMMARY | ||||||
Groups | Count | Sum | Average | Variance | ||
Surprised | 6 | -0.2 | -0.0333 | 0.4987 | ||
Nervous | 6 | -1.4 | -0.2333 | 2.1547 | ||
Scared | 6 | 2.0 | 0.3333 | 2.1547 | ||
Sad | 6 | 2.4 | 0.4000 | 1.1560 | ||
Excited | 6 | 2.2 | 0.3667 | 1.6907 | ||
Angry | 6 | 0.6 | 0.1000 | 0.9560 | ||
ANOVA | ||||||
Source of Variation | SS | df | MS | F | P-value | F crit |
Between Groups | 1.9556 | 5 | 0.3911 | 0.2725 | 0.9246 | 2.5336 |
Within Groups | 43.0533 | 30 | 1.4351 | |||
Total | 45.0089 | 35 |
The Anova table is thus given below.
Source | df | SS | MS | F |
Expressions | 5 | 1.9556 | 0.3911 | 0.2725 |
Error | 30 | 43.0533 | 1.4351 | |
Total | 35 | 45.0089 |