# SOC211H5 Lecture Notes - Lecture 5: Sampling Error, Systematic Sampling, Simple Random Sample

by OC365622

Department

SociologyCourse Code

SOC211H5Professor

kivanchiLecture

5This

**preview**shows half of the first page. to view the full**2 pages of the document.**Sampling error and non- response error

•Sampling error: the extent to which characteristics of the sample deviate from the

characteristics of the population

•It consists of:

•1) Random sampling error: due to chance, assessable by probability calculus: results

are valid at .05 probability level, results are accurate 19 time out of 20

•2) Systematic sampling error: due to sampling design, i.e. to the unequal probability

of sampling elements to be selected into the sample. Unequal probability results in

systematic differences between the selected and the unselected sampling elements

•Non- response error occurs after the sample has been selected serious, because

participants nearly always differ systematically from participants who could not be found

or have refused to participate

•The rich; the homeless, Aboriginals; over-representation of the elderly in survey

samples

•To deal with (sampling and) non-response error: weigh (weight) the statistics by

demographic characteristics of the population

•Population: 49% male, sample: 40% male: weigh each response by a man by 1.225

- 40% men/49% population

Types of Sampling Design

•Probability sampling: probability of selection of each sampling elements is known (not

necessarily equal). Random sampling error is calculable.

•It requires:

•1) a sampling frame

•Known-probability selection of sampling elements

•Non- probability sampling: probability of selection of each sampling element is unknown,

therefore it must be presumed to by unequal. Random sampling error is incalculable

AND there is systematic sampling error.

Types of probability sampling

-Simple random sample: select sampling units from a sampling frame, using random

numbers

- Advantage: known and equal probability of selection (p=n/N).

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