Psychology 394
Repeated Measures ANOVA Assignment
Due: November 14, 2013 by Noon
After their interesting foray into the world of competitive eating, our researchers have established quite a name for themselves. Having read the published results from the competitive eating challenges, a group of producers asked our researchers to attend the taping of a television pilot episode for a new show: The Main Effect of Fear . The show features a competition between participants who will have to master their gag reflex and try to consume unpalatable foods. The producers had the participants consume 5 unpalatable foods for the competition. For their analyses, the researchers recorded the amount of time (in seconds) that it took for the participants to gag or vomit following consumption of the food. Trials were considered complete if the participant kept the item down for 30 seconds. The data are below.
Participant Fermented Fish Pig Intestine Bull Testicle Balut Egg Spoiled Milk
1 12.5 20.0 28.4 12.0 10.4
2
3
13.0
9.1
23.1
20.0
17.9
26.6
7.7
3.4
11.6
11.9
4
5
6
7
5.6
22.3
15.6
15.0
18.6
14.4
15.8
25.4
30.0
30.0
23.5
20.3
5.6
9.3
6.1
13.6
17.2
20.5
22.7
14.1
8
9
14.2
5.9
15.4
25.7
25.1
19.8
6.1
3.8
14.3
25.9
10 3.9 19.8 22.0 9.1 14.2
1.
Run the appropriate ANOVA and include post hoc tests where necessary.
2.
Create an APA format table to report the means and standard deviations of the food types.
Table 1. Time (s) until Gag Reflex as a Function of Food Type.
Food Type
Fermented Fish
Pig Intestine
Bull Testicle
Balut Egg
Spoiled Milk
Mean
11.7100
19.8200
24.3600
7.6700
16.2800
Std. Deviation
5.63214
3.98742
4.35666
3.35064
5.17554

3.
Create an APA format figure (use Excel or Powerpoint) to report the means and standard error of the mean (as error bars). Note: SEM = SD/√N.
30
25
20
15
10
5
0
Fermented Fish Pig Intestine Bull Testicle Balut Egg Spoiled Milk
Food Type
Figure 1. Time (s) until gag reflex as a function of food type. Error bars represent the Standard
Error of the means.
4.
Summarize your findings in an APA format Results section. Refer to your table and figure to present the means.
Mauchly's Test of Sphericity(b)
Measure: MEASURE_1
Epsilon(a)
Within Subjects Effect Mauchly's W
FoodType .329
Approx. Chi-
Square
8.245 df
9
Sig.
.520
Huynh-Feldt
.768
Lower-bound
1.000
Tests the null hypothesis that the error covariance matrix of the orthonormalized transformed dependent variables is proportional to an identity matrix. a May be used to adjust the degrees of freedom for the averaged tests of significance. Corrected tests are displayed in the Tests of Within-Subjects Effects table. b Design: Intercept
Within Subjects Design: FoodType
Greenhouse-
Geisser
.250

Mauchly’s Test of Sphericity is not significant; therefore the assumptions of sphericity are not violated. We will assume spehericity.
Tests of Within-Subjects Effects
Measure: MEASURE_1
Source
FoodType Sphericity Assumed
Greenhouse-Geisser
Huynh-Feldt
Lower-bound
Error(FoodType) Sphericity Assumed
Greenhouse-Geisser
Huynh-Feldt
Lower-bound
Measure: MEASURE_1
FoodType
1
2
3
4
5
Mean
11.710
19.820
24.360
7.670
16.280
Std. Error
1.781
1.261
1.378
1.060
1.637
Type III Sum of Squares
1723.483
1723.483
1723.483
1723.483
811.877
811.877
811.877
811.877
Estimates
95% Confidence Interval
Lower Bound Upper Bound
7.681 15.739
16.968 22.672
21.243
5.273
12.578
27.477
10.067
19.982 df
4
3.072
4.000
1.000
36
27.652
36.000
9.000
Descriptive Statistics
FermentedFish
PigIntestine
BullTesticle
BalutEgg
SpoiledMilk
Mean
11.7100
19.8200
24.3600
7.6700
16.2800
Std. Deviation
5.63214
3.98742
4.35666
3.35064
5.17554
N
10
10
10
10
10
Pairwise Comparisons
Measure: MEASURE_1
Mean Square
430.871
560.956
430.871
1723.483
22.552
29.361
22.552
90.209
F
19.106
19.106
19.106
19.106
Sig.
.000
.000
.000
.002
95% Confidence Interval for
Difference(a)
(I) FoodType (J) FoodType
1 2
3
4
Mean
Difference
(I-J)
-8.110
-12.650(*)
4.040
Std. Error
2.593
2.021
1.686
Sig.(a)
.122
.001
.402
Upper Bound Lower Bound
-17.678 1.458
-20.107 -5.193
-2.181 10.261

5 -4.570
2 1
8.110
3
4
5
-4.540
12.150(*)
3.540
3 1
12.650(*)
2 4.540
4
16.690(*)
4
5
1
2
8.080
-4.040
-12.150(*)
3
-16.690(*)
5 -8.610(*)
5 1
4.570
2
3
4
-3.540
-8.080
8.610(*)
Based on estimated marginal means
* The mean difference is significant at the .05 level. a Adjustment for multiple comparisons: Bonferroni.
Results
2.358
2.593
2.421
1.525
2.139
2.021
2.421
1.766
2.198
1.686
1.525
1.766
2.276
2.358
2.139
2.198
2.276
.846
.122
.935
.000
1.000
.001
.935
.000
.051
.402
.000
.000
.043
.846
1.000
.051
.043
-13.271
-1.458
-13.472
6.522
-4.352
5.193
-4.392
10.175
-.030
-10.261
-17.778
-23.205
-17.007
-4.131
-11.432
-16.190
.213
A Repeated Measures ANOVA with Food Type (5 levels) as a within subjects variable
4.131
17.678
4.392
17.778
11.432
20.107
13.472
23.205
16.190
2.181
-6.522
-10.175
-.213
13.271
4.352
.030
17.007 was performed and a significant main effect was found F(4,36) = 19.106, ME = 22.552, p<.001.
A Post-Hoc test with a Bonferroni correction revealed significant differences. Participants who ate the bull testicle delayed gag reflex for significantly longer than participants in both the fermented fish and balut egg conditions. Participants who ate the pig intestine delayed gag reflex for significantly longer than participants in the balut egg condition. Participants who ate the spoiled milk delayed gag reflex for significantly longer than participants in the balut egg condition also. Participants who consumed the fermented fish gagged significantly sooner than participants in the bull testicle condition. Participants who ate the balut egg gagged significantly sooner than participants in the bull testicle, pig intestine, and spoiled milk conditions. Refer to
Table 1 for the means and standard deviations of each condition. Figure 1 provides a graphical display of the means and standard error of each condition.

( M =24.3600, SD =4.35666)
( M =11.7100, SD =5.63214)
( M =7.6700, SD =3.35064)
( M =19.8200, SD =3.98742)
( M =16.2800, SD= 5.17554)