Sampling method examples
A restaurant leaves comment cards on all of its tables and encourages customers to participate in a brief survey to learn about their overall experience.
Voluntary
I ask random people on the street to take a survey about current events.
Voluntary
I email every student asking them to fill out a survey for yearbook.
Voluntary
A politician asks his neighbors their opinions about a controversial issue.
convenience
A store prints a request on each receipt asking customers to fill out a satisfaction survey online if they are willing.
convenience
A quality control worker at a factory selects the first 10 items she sees as her sample for the day.
Convenience
I ask everyone in my stat's class their favorite color
Convenience
I ask the people parked next to me what they think of carline.
Convenience
Each student at a school has a student identification number. Counselors have a computer generate 50 random identification numbers and those students are asked to take a survey.
Random
Each student at a school has a student identification number. Counselors have a computer generate 50 random identification numbers, and the students associated with those numbers are asked to take a survey.
Random
I want to figure out what stats students think of the class. I assign every student a number then pick 20 numbers out of a hat.
Random
I want to find the weight of the fish in my pond. I assign every fish in the pond a number. I randomly select 10 fish and weigh them.
Random
Employees at a website want to select a sample of their users to ask for a donation. They randomly select one of the first 25 user each day and show them a message asking for a donation. They also show the message to every 25th user from that point on.
Systematic
I ask every third member of the cross country team their preferred course.
Systematic
I look at the roster of graphic design students and select every 4th student to sample.
Systematic
I pull every 1,000th twinkie off the line to test.
Systematic
Using the list of registered voters, I sample every 8th registered Republican to get their opinion on the president
Systematic
While students are lined up for school pictures, a teacher passes out a survey to every 10th student.
Systematic