Chapter 4 · Sampling · Slide 121/274

Sampling: Two General Methods

The sample is drawn based on the personal judgment of the researcher — often at random (convenience sample, e.g. passersby in a shopping mall).

Chapter 4 · Sampling Two General Methods

Sampling: Two General Methods

Method 1

Non-probability Sampling

The sample is drawn based on the personal judgment of the researcher — often at random (convenience sample, e.g. passersby in a shopping mall).

Usually inexpensive; allows a rough estimate of the population parameters.

But: the sampling error cannot be calculated → results are not representative and cannot be generalized to the population.

Method 2

Probability Sampling

The sample is selected based on the principle of randomness.

Allows statistical techniques to determine the accuracy of the estimated population parameters as well as to assess their confidence intervals.

Results are generalizable and can be extended to the population.

QUESTIONSTAR · Dr. Paul Marx 121 / 274

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