Biased and Unbiased Sample

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

• biased

• unbiased

Convenience sample and voluntary response sample are types of...

• biased samples

• unbiased samples

To determine how many students at Shull would attend the dance, the principal surveyed the students in Ms. Miller's math class. 10 students said they would attend and 15 said they would not attend. It can be concluded that half the students at Shull will attend the dance. Is this conclusion valid? Why or why not?

• Yes, this is a simple random sample. So the sample is unbiased.

• No, this is a convenience sample. So the sample is unbiased.

• No, this is a voluntary response sample. So the sample is biased.

• No, this is a convenience sample. So the sample is biased.

The Student Council asked every tenth student in the lunch line how they preferred to be contacted with school news. The results are shown in the table. Is this an unbiased sample? If yes, suppose there are 684 students at the school. How many can be expected to prefer E-mail?

• No, it's a biased sample

• 432

• 304

• 16

At Centre 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 Beta Club to choose a location

You want to know what is the most favorite sport of 7th graders at BVMS. You ask 7th graders who want to participate to go to the office 5th period to complete a survey. This is...

• Biased, because it is a convenience sample

• Unbiased

• Biased because it is an interval sample

• Biased because it is a volunteer 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?

Biased or Unbiased?

John wants to find out what the favorite soda flavor is at Menifee County. He decides to ask all the students in Mr. Goldsmith's class as a sample group.

• Biased

• Unbiased

To evaluate the defect rate of its memory chips, an integrated circuit manufacturer tests every 100th chip off the production line.

• 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