Biased Unbiased Sample Population

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

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

To get valid results, a sample must be...

• biased

• unbiased

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.

Casey surveyed the members of his soccer team to ask them what their favorite sport is. Is this a biased sample or unbiased sample?

• Biased Sample

• Unbiased Sample

Shelley wants to survey grocery shoppers about their favorite brands. She goes to the store at 8am and surveys the first 50 people. Is this a biased sample or unbiased sample?

• Biased Sample

• Unbiased Sample

A school district wants to know if parents would prefer to get phone calls or emails from the schools. They survey the parents of all the seventh grade students enrolled in the district. Is this a biased sample or unbiased sample?

• Biased Sample

• Unbiased Sample

An airline wants to know if people prefer to check their luggage or carry it on. They ask every 10th person that walks into the airport. Is this a biased sample or unbiased sample?

• Biased Sample

• Unbiased sample?

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

• Biased Sample

• Unbiased Sample

A company makes DVDs and randomly selects 25 from 1500 to test them to see if they work.

• Biased

• Unbiased