Anova Response Time
1. **Problem Statement:**
We want to determine if server type (A, B, C), region (North, South), and their interaction significantly affect response time.
2. **Method:**
Use Two-Way ANOVA to analyze the effects of two categorical independent variables (server type and region) on a continuous dependent variable (response time).
3. **Data Summary:**
- Server A North: 120, 130, 125
- Server A South: 140, 135, 138
- Server B North: 110, 115, 112
- Server B South: 150, 145, 148
- Server C North: 100, 105, 102
- Server C South: 160, 155, 158
4. **Calculate group means:**
- $\bar{X}_{A,N} = \frac{120+130+125}{3} = 125$
- $\bar{X}_{A,S} = \frac{140+135+138}{3} = 137.67$
- $\bar{X}_{B,N} = \frac{110+115+112}{3} = 112.33$
- $\bar{X}_{B,S} = \frac{150+145+148}{3} = 147.67$
- $\bar{X}_{C,N} = \frac{100+105+102}{3} = 102.33$
- $\bar{X}_{C,S} = \frac{160+155+158}{3} = 157.67$
5. **Calculate overall mean:**
$$\bar{X} = \frac{\sum \text{all values}}{18} = \frac{120+130+125+140+135+138+110+115+112+150+145+148+100+105+102+160+155+158}{18} = 132.5$$
6. **Calculate main effects means:**
- Server type means:
- $\bar{X}_A = \frac{125 + 137.67}{2} = 131.33$
- $\bar{X}_B = \frac{112.33 + 147.67}{2} = 130$
- $\bar{X}_C = \frac{102.33 + 157.67}{2} = 130$
- Region means:
- $\bar{X}_N = \frac{125 + 112.33 + 102.33}{3} = 113.89$
- $\bar{X}_S = \frac{137.67 + 147.67 + 157.67}{3} = 147.67$
7. **ANOVA model:**
Response time $= \mu + \alpha_i + \beta_j + (\alpha\beta)_{ij} + \epsilon_{ijk}$
- $\mu$: overall mean
- $\alpha_i$: effect of server type $i$
- $\beta_j$: effect of region $j$
- $(\alpha\beta)_{ij}$: interaction effect
- $\epsilon_{ijk}$: random error
8. **Interpretation:**
- Large differences in means suggest server type and region affect response time.
- Interaction is suggested by different differences between North and South across server types.
9. **Conclusion:**
Performing the full ANOVA test (calculating sums of squares, degrees of freedom, mean squares, and F-statistics) will confirm significance.
Since the question is about evaluation, the data shows clear differences in response times by server type and region, and interaction likely exists.
Final answer: Server type, region, and their interaction significantly affect response time based on observed means.