Practice with Sampling Methods

A mid-size paper company wishes to take a random sample of its clients. Clients are divided into Small (under $50k), Medium ($50k to $250k), and Large (over $250k). A random digits table is used to select 30 small, 15 medium, and 10 large clients.

• Convenience

• Stratified

• Voluntary

• Cluster

An ultimate frisbee tournament organizer wants to estimate the mean number of years of playing experience for its participants. She uses a list of all participants, numbered 001 to 312, and a random digits table to select 25 participants.

• Convenience

• Stratified

• Voluntary

• Simple Random Sample

A restaurant manager wants to gauge the opinion of the restaurant’s customers. He walks around and interviews 20 people who are eating there one Saturday night.

• Convenience

• Stratified

• Voluntary

• Simple Random Sample

A comic book store wishes to take a sample of comic books. Their inventory is currently stored in cardboard boxes. The manager numbers each box from 001 to 684 and uses a random digits table to select 20 random boxes. All comics in these boxes are included in her sample.

• Convenience

• Stratified

• Cluster

• Simple Random Sample

An exit poller wants to estimate the proportion of voters who voted for certain candidates. He stands outside a particular polling place at 10am and interviews the first 100 voters to exit.

• Convenience

• Stratified

• Cluster

• Simple Random Sample

Tobias wants to watch a random sample of Simpsons episodes from the first 10 seasons (which are the best). He chooses an SRS of 3 episodes from each of these ten seasons, and watches these episodes.

• Convenience

• Stratified

• Cluster

• Simple Random Sample

To choose a sample of fifty employees from a large corporate office, a list of employees is obtained, alphabetized, and labeled numerically. A random digits table is read left to right, in sets of threes, until fifty unique labels are found. These fifty employees are used in the sample

• Convenience

• Stratified

• Cluster

• Simple Random Sample

A local newspaper wishes to estimate the years of graduate education that the teachers in the local school district have obtained. A mass email is sent to all teachers in the district asking them to reply with the number of years of graduate education obtained.

• Convenience

• Voluntary/Self-selected

• Cluster

• Simple Random Sample