Sample Methods & Bias

Interview the first 30 students who enter the school in the morning. 

• simple random
• voluntary response
• systematic
• convenience

Disneyland often surveys its guests as they exit a restaurant during their visit. The surveyor stands at the restaurant exit, counts the number of people leaving, and surveys every 25th guest.
This is a form of:

• Random Sample
• Convenience Sampling
• Voluntary Response
• Systematic Sampling

A teacher wants to know the average time spent doing homework by the students in her class of 20 girls and 5 boys.
She selects the first five who raise their hands.

• Systematic
• Convenience
• Voluntary Response
• Simple Random

Survey 10 students from every classroom in a building on campus.

• Convenience

• Systematic

• Stratified

• Simple Random

What type of Sampling?

At a local community college, five math classes are randomly selected out of 20 and all of the students from each class are interviewed.

• Random

• Stratefied

• Systematic

• Cluster

What type of Sampling?

A researcher for an airline interviews all of the passengers on five randomly selected flights.

• Random

• Stratefied

• Systematic

• Cluster

Identify the sampling design: School admin conducted a survey on post-graduation plans.  Students of senior class 2018 were listed in order by class rank.  The school selected a random number between 1 and 15, obtaining a number 11.  Then, they selected every 11th student for the survey.

• cluster
• volunteer
• systematic
• simple random

Determine if the following study is biased.

A public library asked every 10th person who entered to name the type of book they were getting.

• A. Biased

• B. Unbiased

Determine if the following study is biased.

Carlos wants to know the favorite sport of people at his school so he asks his baseball team.

• A. Biased

• B. Unbiased

11. Larger random sample sizes are more representative of a population.

• A. True
• B. False