Skip to main content
Ch. 12 - Analysis of Variance
Triola - Elementary Statistics 14th Edition
Triola14th EditionElementary StatisticsISBN: 9780137366446Not the one you use?Change textbook
All textbooksTriola 14th EditionCh. 12 - Analysis of VarianceProblem 12.2.5
Chapter 12, Problem 12.2.5

Car Crash Test Measurements If we use the data given in Exercise 1 with two-way analysis of variance and a 0.05 significance level, we get the accompanying display. What do you conclude?
"ANOVA table with sources: Interaction, Row, Column; showing DF, SS, MS, Test Stat, Critical F, and P-Value."

Verified step by step guidance
1
Step 1: Understand the context of the problem. This is a two-way ANOVA test, which is used to analyze the effect of two independent variables (factors) on a dependent variable, as well as their interaction. The table provides the results of the analysis, including degrees of freedom (DF), sum of squares (SS), mean square (MS), F-statistic, critical F-value, and P-value for each source of variation.
Step 2: Interpret the interaction row. The interaction term tests whether the two factors interact significantly. Compare the P-value (0.01028) to the significance level (0.05). If the P-value is less than 0.05, conclude that there is a significant interaction effect between the two factors.
Step 3: Interpret the row variable. This term tests the main effect of the row variable (one of the factors). Compare the P-value (0.14832) to the significance level (0.05). If the P-value is greater than 0.05, conclude that the row variable does not have a significant main effect.
Step 4: Interpret the column variable. This term tests the main effect of the column variable (the other factor). Compare the P-value (0.01084) to the significance level (0.05). If the P-value is less than 0.05, conclude that the column variable has a significant main effect.
Step 5: Summarize the conclusions. Based on the P-values, there is a significant interaction effect between the two factors, no significant main effect for the row variable, and a significant main effect for the column variable. These conclusions should guide further analysis or decision-making.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
6m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Two-Way ANOVA

Two-way ANOVA is a statistical method used to determine the effect of two independent categorical variables on a continuous dependent variable. It assesses not only the individual impact of each factor but also the interaction between them. This technique helps in understanding how different groups compare and whether their means are significantly different.
Recommended video:
Guided course
03:50
Probabilities Between Two Values

F-Statistic

The F-statistic is a ratio used in ANOVA to compare the variance between group means to the variance within the groups. A higher F-statistic indicates a greater disparity between the group means relative to the variability within the groups, suggesting that at least one group mean is significantly different from the others. It is crucial for determining the significance of the results.
Recommended video:
Guided course
05:53
Parameters vs. Statistics

P-Value

The p-value is a measure that helps determine the significance of the results in hypothesis testing. It indicates the probability of observing the data, or something more extreme, assuming the null hypothesis is true. A p-value less than the significance level (e.g., 0.05) suggests that the null hypothesis can be rejected, indicating a statistically significant effect.
Recommended video:
Guided course
06:50
Step 3: Get P-Value
Related Practice
Textbook Question

Two-Way Anova If we have a goal of using the data given in Exercise 1 to (1) determine whether the femur side (left, right) has an effect on the crash force measurements and (2) to determine whether the vehicle size has an effect on the crash force measurements, should we use one-way analysis of variance for the two individual tests? Why or why not?

Textbook Question

Weights from ANSUR I and ANSUR II The following table lists weights (kg) of randomly selected U.S. Army personnel obtained from the ANSUR I study conducted in 1988 and the ANSUR II study conducted in 2012. If we use the data with two-way analysis of variance and a 0.05 significance level, we get the accompanying display. What do you conclude?

Textbook Question

Distance Between Pupils The following table lists distances (mm) between pupils of randomly selected U.S. Army personnel collected as part of the ANSUR II study. Results from two-way analysis of variance are also shown. Use the displayed results and use a 0.05 significance level. What do you conclude? Are the results as you would expect?

Textbook Question

Pancake Experiment Listed below are ratings of pancakes made by experts (based on data from Minitab). Different pancakes were made with and without a supplement and with different amounts of whey. The results from two-way analysis of variance are shown. Use the displayed results and a 0.05 significance level. What do you conclude?

Textbook Question

Two-Way Anova The measurements of crash test forces on the femur in Table 12-3 from Example 1 are reproduced below with fabricated measurement data (in red) used for the left femur in a small car. What characteristic of the data suggests that the appropriate method of analysis is two-way analysis of variance? That is, what is “two-way” about the data entered in this table?

Textbook Question

Tukey Test A display of the Bonferroni test results from Table 12-1 (which is part of the Chapter Problem) is provided here. Shown on the top of the next page is the SPSS-generated display of results from the Tukey test using the same data. Compare the Tukey test results to those from the Bonferroni test.

1
views