Balanced Design Does the table given in Exercise 1 constitute a balanced design? Why or why not?
Table of contents
- 1. Intro to Stats and Collecting Data55m
- 2. Describing Data with Tables and Graphs1h 55m
- 3. Describing Data Numerically1h 45m
- 4. Probability2h 16m
- 5. Binomial Distribution & Discrete Random Variables2h 33m
- 6. Normal Distribution and Continuous Random Variables1h 38m
- 7. Sampling Distributions & Confidence Intervals: Mean1h 53m
- 8. Sampling Distributions & Confidence Intervals: Proportion1h 12m
- 9. Hypothesis Testing for One Sample2h 19m
- 10. Hypothesis Testing for Two Samples3h 22m
- 11. Correlation1h 6m
- 12. Regression1h 4m
- 13. Chi-Square Tests & Goodness of Fit1h 20m
- 14. ANOVA1h 0m
9. Hypothesis Testing for One Sample
Steps in Hypothesis Testing
Problem 12.1.1a
Textbook Question
In Exercises 1–4, use the following listed measured amounts of chest compression (mm) from car crash tests (from Data Set 35 “Car Data” in Appendix B). Also shown are the SPSS results from analysis of variance. Assume that we plan to use a 0.05 significance level to test the claim that the different car sizes have the same mean amount of chest compression.

Anova
a. What characteristic of the data above indicates that we should use one-way analysis of variance?

1
Step 1: Identify the groups in the data. The table shows measured amounts of chest compression (mm) for four different car sizes: Small, Midsize, Large, and SUV. Each group represents a distinct category of car size.
Step 2: Recognize the dependent variable. The dependent variable in this case is the measured amount of chest compression (mm), which is a continuous numerical variable.
Step 3: Understand the purpose of one-way ANOVA. One-way analysis of variance (ANOVA) is used to compare the means of more than two groups to determine if there is a statistically significant difference among them. Here, we are testing the claim that the different car sizes have the same mean chest compression.
Step 4: Note the requirement for one-way ANOVA. One-way ANOVA is appropriate when there is one independent variable (car size) with multiple levels (Small, Midsize, Large, SUV) and one dependent variable (chest compression). This data meets the criteria because car size is the independent variable with four levels, and chest compression is the dependent variable.
Step 5: Confirm the assumption of independence. The data appears to be grouped by car size, and the measurements within each group are independent of each other, which is a key assumption for one-way ANOVA.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
One-Way Analysis of Variance (ANOVA)
One-way ANOVA is a statistical method used to compare the means of three or more independent groups to determine if at least one group mean is significantly different from the others. It assesses the impact of a single categorical independent variable on a continuous dependent variable, making it suitable for experiments with multiple groups, such as different car sizes in this case.
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Difference in Means: Hypothesis Tests
Assumptions of ANOVA
ANOVA relies on several key assumptions: the samples must be independent, the data should be normally distributed within each group, and the variances among the groups should be approximately equal (homogeneity of variance). Checking these assumptions is crucial before performing ANOVA to ensure valid results and interpretations.
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Step 1: Write Hypotheses Example 1
Significance Level (α)
The significance level, often denoted as alpha (α), is the threshold for determining whether the observed results are statistically significant. In this context, a significance level of 0.05 indicates that there is a 5% risk of concluding that a difference exists when there is none. It is used to decide whether to reject the null hypothesis, which states that all group means are equal.
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Step 4: State Conclusion Example 4
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