In: Statistics and Probability
1) Look at the statistical analyzes that I have provided. Now, identify the next necessary step related to the statistical conclusions I have reached. (Hint: It has to do with t-tests)
Here are the results of the Observation Study data analysis.
Descriptive Statistics
Independent Variable 1 - Gender: a categorical variable
N = 1042 (frequencies: Male = 469, Female = 573)
Independent Variable 2 - Behavior: a categorical variable
N = 1042 (frequencies: Cell = 184, MP3 = 84, None = 774)
Dependent Variable - Looks: a continuous measure
# Looks |
0 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
Frequency |
186 |
306 |
346 |
123 |
52 |
21 |
5 |
3 |
N = 1117 Mean = 1.66 Standard Deviation = 1.242 Range = 7
Inferential Statistics:
I ran a 2 (Gender: Male vs. Female) X 3 (Behavior: Cell vs. MP3 vs. None) ANOVA with the number of looks as the Dependent Variable. Here are the results…
Source |
Sum of Squares |
df |
Mean Square |
F |
Sig. |
Gender |
2.157 |
1 |
2.157 |
1.435 |
.231 |
Behavior |
35.298 |
2 |
17.649 |
11.745 |
.000 |
Gender * Behavior |
11.951 |
2 |
5.975 |
3.976 |
.019 |
Residual |
1556.788 |
1036 |
1.503 |
||
Total |
4481.000 |
1042 |
Condition Means (marginal means in bold)
Cell |
MP3 |
None |
||
Men |
1.714 |
2.000 |
1.694 |
1.73 |
Women |
1.800 |
2.528 |
1.485 |
1.61 |
1.76 |
2.23 |
1.58 |
From the results of the two-way ANOVA, we can conclude that there is no significant differences in the Number of looks between males & females as the p-value=0.231>0.05.
The behaviour variable is significant as the p-value = 0.000<0.05 is significant for it. Therefore, it means that atleast two groups within Behaviour have significant differences in the number of looks but we are not aware of which groups. Hence, for this purpose, we need to run a post-hoc test. As we have three levels within Behaviour which are (Cell, MP3, None), LSD post-hoc test would be appropriate here. The post=hoc results would tell us that which levels have a significant difference between each other. Also, we could run a post-hoc test on the interaction variable to know which level of the factors interact with each other.
The post-hoc tests check the difference between two groups pairwise so it is related to t-tests but adjusts the familywise error rate to 0.05 rather than individually adding up the error rates for each pairwise comparison done.