In: Statistics and Probability
The data below represent scores from three different therapies used to treat depressive symptoms. Scores represent depressive symptoms on a scale of 1-10, with higher scores indicating greater depressive symptoms.
Treatment 1 |
Treatment 2 |
Treatment 3 |
|
0 |
1 |
4 |
|
0 |
4 |
3 |
G = 24 |
0 |
1 |
6 |
ΣX2 = 92 |
2 |
0 |
3 |
_______ |
T1 = 2 |
T2 = 6 |
T3 = 16 |
|
SS1 = 3 |
SS2 = 9 |
SS3 = 6 |
a. SST is what?
b. SSW is what?
c. SSB is what?
d dfT is what?
e. dfW is what?
f. dfB is what?
g. MSB is what?
h. MSW is what?
i. F is what?
j. η2 is what?
k. Statistically significant?
l. Tukey HSD critical value is what?
m. APA Conclusion?
Answer :
By using Excel :
Path : data < data analysis < anova for single factor
SUMMARY | ||||||
Groups | Count | Sum | Average | Variance | ||
treatment 1 | 4 | 2 | 0.5 | 1 | ||
Treatment 2 | 4 | 6 | 1.5 | 3 | ||
Treatment 3 | 4 | 16 | 4 | 2 | ||
ANOVA | ||||||
Source of Variation | SS | df | MS | F | P-value | F crit |
Between Groups | 26 | 2 | 13 | 6.5 | 0.017914 | 4.256495 |
Within Groups | 18 | 9 | 2 | |||
Total | 44 | 11 |
a) SST = 26 = sum of square of treatment = also called between sum of square
b) SSW = Within sum of square = 18
c) SSB = between sum of square =26
d) Degrees of freedom of Treatment = dfT =2
e) Within Degrees of freedom = dfW=9
f) between Degrees of freedom= dfB=2
g) Between mean sum of square = MSB=13
h) within mean sum of square = MSW=2
i) F value= 6.5
j) η2 = F script = 4.2564
k) Here p-value = 0.017 is greater than 0.05 level of significance.
then we accept Ho at 5 % los.
Hence , There is statistically significant .
l) we have to find Tukey HSD critical value :
From above analysis,
The value of the Tukey test is given by taking the absolute value of the difference between pairs of means and dividing it by the standard error of the mean (SE) as determined by a one-way ANOVA test.
difference | n (group 1) | n (group 2) | SE | q | ||
t1 | t2 | 1 | 4 | 4 | 0.7071 | 1.414227 |
t2 | t3 | 2.5 | 4 | 4 | 0.7071 | 3.535568 |
t3 | t1 | 3.5 | 4 | 4 | 0.7071 | 4.949795 |
Hence , this are Tukey HSD critical values.
m) APA Conclusion:
ANOVA and post hoc tests ANOVAs are reported like the t test, but there are two degrees-of-freedom numbers to report. First report the between-groups degrees of freedom, then report the within-groups degrees.