Question

to estimate the percentage of defects in a recent manufacturing batch, a quality-control manager selects every twentieth widget that comes off the assembly line, starting with the tenth, until he obtains a sample of sixty widgets.

what type of sampling method is used?

Explanation:

Identify the sampling procedure

The scenario describes a quality-control manager selecting every twentieth widget (\(k = 20\)) starting with the tenth widget (\(start = 10\)) off an assembly line. This involves selecting members of a population at a regular, predetermined interval.

Analyze the characteristics of the method

Using the Sampling Methods knowledge point, we evaluate the characteristics of this selection process:

• It does not rely on convenience or voluntary response.
• It does not divide the population into distinct groups (strata or clusters).
• Instead, it uses an ordered system with a fixed periodic interval to select individuals.

Determine the specific sampling type

A method where sample members from a larger population are selected according to a random starting point but with a fixed, periodic interval is called systematic sampling.

Answer:

What type of sampling method is used?
<blank>Systematic sampling</blank>