Sampling techniques

A computer program generates telephone numbers at random from a purchased list for poll workers to call. This is an example of (blank) sampling

Answer explanation

Remember that simple random sampling is considered a fair way of selecting terms from a population. Random does not mean haphazard!

Ohio has 607 school districts. In order to find out if a breakfast program is of interest, a random sample of 50 school districts will be chosen. Out of those districts chosen, 20 schools will be randomly selected and surveyed on interest in the program. This is an example of (blank) sampling.

• Cluster

• Multistage

• simple random

• systematic

Answer explanation

Multistage sampling involves taking random selections from clusters in stages.

Ohio has 607 school districts. In order to find out if a breakfast program is of interest, a random sample of 50 school districts will be chosen. Out of those districts chosen, all schools in those districts will be surveyed on interest in the program. This is an example of (blank) sampling.

• Simple random

• Systematic

• Multistage

• Cluster

Answer explanation

With cluster sampling, the population is divided into clusters and a random sample of those clusters is taken. A census is taken of every item in the cluster.

In a factory, if an inspector selects every 50th item on the assembly line to check for defects, this is (blank) sampling.

Answer explanation

Systematic sampling is used frequently in manufacturing.

The names of 20 volunteers for a committee are written on index cards and placed into an envelope. Those envelopes are put into a bag and shuffled. Four envelopes are chosen from the bag. This is an example of (blank) sampling.

Answer explanation

With random samples, every item has the same chance of being chosen.

Ohio Department of Education has classified districts into 8 typology codes based on shared demographic and geographic characteristics. 5 districts from each topology code are selected. This is an example of (blank) sampling.

• Simple random

• Systematic

• Stratified

• Cluster

• Multistage

Answer explanation

Stratified sampling splits the population into strata and a sample is chosen from each stratum. Here the strata are the 8 typology codes.

A market researcher is studying whether expansion for a company is in order within Akron, Ohio. They take a sample of 20 residents within each of the 10 wards. This is an example of (blank) sampling

Answer explanation

Here the strata are the 10 wards in Akron.

Suppose you are to survey the birds on a plot of land. You take a map of the plot and divide the plot into 100 squares all of equal size. 20 squares are chosen at random from the map and all of the birds are counted within the squares. This is an example of (blank) sampling.

• Simple random

• Stratified

• Systematic

• Multistage

• Cluster

Answer explanation

Here the clusters are the squares on the map. This is cluster sampling since every bird was counted within the squares.

If you were to ask the first 100 customers at Dunkin Donuts on a Monday morning how much they spent, this sample would exhibit (blank) since the sample may not accurately reflect the population of Dunkin Donuts customers.

Answer explanation

This sample would be biased since it systematically favors those who visit DD on Monday morning.

A phone manufacturer wants to check the quality of their phones. Every hour, 5 phones are pulled off the assembly line to be checked for quality. This is an example of (blank) sampling.

Answer explanation

There is a gap or interval between each selected unit in the sample. In this case, the gap is every hour.