---
url: "https://questionstar.com/principles-of-survey-research/chapter-5/slide-173.html"
title: "Measures of Dispersion"
type: "lehrbuch-slide"
chapter: 5
chapterTitle: "Data Analysis: A Concise Overview of Statistical Techniques"
slide: 173
---

# Measures of Dispersion

*The mean acts like a balance point – the average deviation from the mean is always zero.*

Sample Variance

![s² = ∑(xᵢ − x̄)² / (n − 1)](/principles-of-survey-research/media/formel_varianz_sample.png)

Why variance?

![x̄ = (1.5 + 2.5 + 3.5 − 0.5 + 4.5 + 1.5 − 2.5 − 6.5 + 2.5 − 0.5 − 2.5 − 3.5) / 12 = 0](/principles-of-survey-research/media/formel_mw_null.png)

The mean acts like a **balance point** – the average deviation from the mean is always zero.

In the variance, all deviations are **squared** , so that negative and positive deviations do **not cancel out** .

![s² = 117 / (12 − 1) ≈ 10.6](/principles-of-survey-research/media/formel_s2_beispiel.png)

*[Diagramm: Measures of Dispersion]*

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*Slide 173 of 274 · Chapter 5: Data Analysis: A Concise Overview of Statistical Techniques · Principles of Survey Research · Dr. Paul Marx*