1. Homogeneity

2. Contents
What is homogeneity?
Why is homogeneity important?
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3. What is homogeneity?
Homogeneity refers to the degree the members of a population are relatively similar along important dimensions.
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4. What is homogeneity? Example with a Character Variable.
This population is heterogeneous with respect to employee status.
Union and Management Employees
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5. What is homogeneity? Example with Numeric Variable (age).
This distribution is bimodal. If necessary, it can be batched into two groups.
= younger group
= older group
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6. What is homogeneity? Example with Numeric Variable (salary).
This distribution is skewed. If necessary, it can be batched into two groups.
= Higher paid (outliers)
= Lower paid (normally distributed)
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7. Contents
What is homogeneity?
Why is homogeneity important?
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8. Why is homogeneity important?
Homogeneity affects the interpretability of your survey results. The estimates you calculate from a sample are meant to represent all members of a population.
Survey estimates from a very heterogeneous population might not be representative of any of the members.
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9. Why is homogeneity important?
A sample from a heterogeneous population might contain a single or a few outliers, and this will affect the validity of the results.
Value of the outlier may be very different than the rest of the sample. This will skew the results and the sample estimate will not reflect the population.
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10. Example: Impact of an Outlier.
Survey question: What is your yearly net income?
The estimate of $47,000 does not accurately reflect either the “green” members, or the “blue” members of the population.
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11. Why is homogeneity important?
A sample from a heterogeneous population might contain members from two very different populations.
The averaged results from the “red” and the “green” members may result in an estimate that reflects neither group.
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12. Example: Impact of two populations.
Survey question: Do you like the management style of your organization?
The estimate of 50% is misleading, and we have failed to notice that one segment of the population is very unsatisfied, and another is very satisfied.