Sampling Methods and Types of Variables

Each law firm in one state registers its phone number with the state court system. An employee of the state court system uses a computer to select 500 random registered phone numbers, and the law firms associated with those numbers will be selected for an audit.

• Simple Random Sampling

• Stratified Sampling

• Cluster Sampling

• Systematic Sampling

A support hotline asks callers to stay on the line after they have completed their call to respond to a short survey.

• Simple Random Sampling

• Stratified Sampling

• Non-random sample

• Systematic Sampling

A manager at a pizza shop wants to start visually checking finished pizzas, but she doesn't have time to check every pizza. She decides to check a random pizza from the first 20 made each day, and then check every 20th pizza thereafter.

• Simple Random Sampling

• Cluster

  Sampling

• Non-random sample

• Systematic Sampling

A student council surveys 100 students by taking random samples of 25 freshmen, 25 sophomores, 25 juniors, and 25 seniors (assume equal # of students from each group).

• Simple Random Sampling

• Cluster

  Sampling

• Non-random sample

• Stratified Sampling

What type of variable is "the type of sporting events at the Olympic Games" if for example "athletics, footbal" are encoded with values 1 and 2, respectively

• qualitative categorical

• qualitative ordinal

• quantitative discrete

• quantitative continuous

What type of variable is "income" if the data available is "low income, middle income, high income"

• qualitative categorical

• qualitative ordinal

• quantitative discrete

• quantitative continuous

What type of variable is "Grade in the midterm exam"?

• continuous, so long as there are decimals included

• discrete, if grades are only set in units

• could also be qualitative

• all of them are correct