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Responding driven sampling Principles of Sampling Session 1

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After this session, you should be able to Outline the purpose of sampling Understand key theoretical concepts in sampling Describe the concept of selection bias and random error in sampling 2WWW.HIVHUB.IR

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Why do we sample? We sample when we desire to measure characteristics of a specified population (e.g., the proportion of the general population who have unsafe sex) but lack the time and resources to obtain information from all members of the population. Concentrating survey time and resources on a sample may also result in better quality data than if resources were spread over the whole population. 3WWW.HIVHUB.IR

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Key definitions Sampling unit (element): Subject under observation on which information is collected Example: adults

Target population-> Study Population-> Sample 7WWW.HIVHUB.IR Target Population: All homeless in country X Study Population: All homeless in capital shelters in the Sample: Homeless at particular shelter