Ugrás a tartalomhoz

SOCIAL STATISTICS

Renáta Németh, Dávid Simon

ELTE

Introduction

Introduction

Objective: to select a single number that summarizes the distribution.

Measures of central tendency focus only on one aspect.

Another aspect: how much variation there is in the distribution.

Measures of variability.

A motivating example: ISSP data, 2006.

„In the last five years, how often have you or a member of your immediate family come across a public official who hinted they wanted, or asked for, a bribe or favor in return for a service?”

Latvia

Hungary

Denmark

Never

54.3

77.7

95.2

Seldom

22.6

10.8

3.6

Occasionally

17.4

8.2

.9

Quite often

4.5

2.8

.2

Very often

1.2

.5

.1

The mode is less informative here. Why?

Consider an interval-ratio variable: Monthly net income. ISSP, 1998, Hungary. By education:

Level of education = High school degree

Mean: 38,665 Ft

Level of education = College

Mean: 38,988 Ft

While the lowest and highest income in the two groups are:

Level of education = High school degree

Minimum: 4,000 Ft

Maximum: 500,000 Ft

Level of education = College

Minimum: 10,800 Ft

Maximum: 200,000 Ft