Population Sampling and Biased and Unbiased Sampling 7th G

Identify the Population:
Wicomico County Public Schools randomly selected 230 teachers to find out which technology resource it's teachers feel is the most effective.

• 230 Teachers
• All Wicomico County Teachers
• Students
• Wicomico County Public Schools

Identify the Sample:
A restaurant wants to know if their customers buy dessert when they eat out. As people leave the restaurant one evening, 20 people are surveyed at random. Eight people say they usually order dessert when they eat out. The restaurant concluded that most customers do not order dessert.

• 20 customers
• All customers
• 8 customers
• Dessert

If I wanted to know how many blades of grass are inside the track, which sampling method could I use?

• Have my students count every blade of grass
• Guess
• Divide the grassy area into 1 inch sections, randomly pick several sections to count, average them together and multiply that by the total square inches.

Ana wants to know the average student’s opinion of the tardy policy at her school. Which group of students should she survey in order to achieve the most accurate results?

• thirty students who are often tardy
• thirty students who are rarely tardy
• thirty of her friends
• thirty randomly selected students from her school

At a middle school, the 7th graders will conduct a survey to decide where they want to go on a field trip. Which method will result in the least biased decision?

• to randomly ask 8th grade students who went on a field trip last year
• to randomly choose some 7th grade students to select a location
• to ask all 7th grade teachers and administrators for a location
• to ask the student council to choose a location

Unbiased sampling is:

• when you choose the group you think will give you the answer you want, accept volunteers or survey by convenience
• when any member of the population is equally likely to be chosen for the sample

To determine the most popular children’s programs, a television station asks parents to call in and complete a phone survey.

• Biased Sample

• Unbiased Sample

Airline boarding passes are marked with red stars at random to decide which passengers should have their carry-on luggage inspected.

• Biased Sample

• Unbiased Sample

To determine how often people eat out, every tenth person entering a Chinese restaurant is surveyed.

• Biased Sample

• Unbiased Sample

To determine the most common injury cared for in an emergency room, a reporter goes to the same hospital every afternoon for one month during the summer and observes people entering the emergency room. She concludes that second degree sunburn is the most common injury.

• Unbiased

• Biased