Answers -- Review for Exam 1
1. A one-way ANOVA was conducted to examine the differences in the three groups on change in attitude. The means and standard deviations for the three groups on change in attitude are reported in Table 1. The assumption of homogeneity of variance was not violated, F(2, 15)=.42, p=.67. There was a significant difference between the three groups on change in attitude, F(2, 15)=6.32, p=.01, h^{2}=.46. Tukey’s post hoc comparisons indicated that the inoculation group had a significantly lower means than both the support and control groups (p<.05).
Table 1
Group |
M |
SD |
support |
5.33 |
1.63 |
inoculation |
3.00 |
1.41 |
control |
6.00 |
1.55 |
2. A two-way ANOVA was conducted to examine the effects of worker status and type of work on productivity. The assumption of equality of error variances was tenable, F=1.12, p=.37. The means and standard deviations for productivity are reported in the table below. There were statistically significant main effects for both type of work (F=21.77, p<.001, h^{2}=.55) and worker status (F=6.84, p=.003, h^{2}=.28). There was no significant interaction between the factors (F=2.01, p=.11, h^{2}=.18). Tukey’s post hoc procedures indicated that low status workers had significantly lower productivity mean rates than both the medium and high status workers. Workers who worked in groups had the highest productivity rates followed by pairs of workers, and the workers who worked in solitary had the lowest productivity mean rate.
3. There were statistically significant inverse associations between IQ and risk factors (r=-.679, p=.015) and IQ and self defiance (r=-.90, p<.001). The data suggest that individuals with higher IQ tend to have lower risk factors and lower self defiance.
4. The means and standard deviations for the the before and after mean scores are in the table below. A dependent t-test was conducted to examine the difference between the before and after. The results indicated that there was no significant difference between the mean scores, t(4)=2.08, p=.11.
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5. A three-group MANOVA was conducted to examine the differences between the three groups and the dependent variables: assist and resist. The means and standard deviations are reported in the table below. The assumption of equal of covariance matrices was satisfied, Box's M=7.17, F=.96, p=.45. There was a statistically significant difference between the three groups and the combined dependent variables, Wilks' Lambda=.15, F=10.90, p<.001, eta squared=.61. Univariate results indicated that differences were detected for both assist (F=6.32, p=.01) and resist (F=26.08, p<001). Tukey's post hoc procedures indicated that group 2 was significantly lower than both group 1 and 3 on assist, and group 2 was significantly higher that groups 1 and 3 on resist.
6.
A 2X2 MANOVA was conducted to examine the gender and parent educational level on reading and math.