Sample Size and Sampling Errors

Introduction

Choosing the right sample size is important for reliable research results.

A sample that is too small may not represent the population well.


Factors Affecting Sample Size

  • Population size
  • Research objectives
  • Available time
  • Budget
  • Desired accuracy

Common Sampling Errors

Selection Bias

Some groups are unfairly excluded.


Nonresponse Error

Selected participants do not respond.


Sampling Bias

The sample does not represent the population accurately.


Example

If a survey about internet usage only includes urban residents, rural populations may be excluded.

This creates bias.


Tips to Reduce Errors

  • Use appropriate sampling methods
  • Increase response rates
  • Ensure diversity in the sample

Quick Check

What happens if a sample is not representative?