Techniques Used to Get Unbiased Results

What type of sampling method was used?

• Simple Random Sample

• Systematic Random Sample

• Convenience Sample

• Voluntary Response Sample

What type of sampling methods would be the most likely to produce VALID survey results?

• Unbiased or fair sampling

• Biased or unfair sampling

• Unbiased or unfair sampling

• Biased or fair sampling

Green Valley Middle School conducted a survey of 125 random students asking them how much time they spend each night on homework. Is this a biased sample or unbiased sample?

• Biased Sample

• Unbiased Sample

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.

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.

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 get valid results, a sample must be...

• biased

• unbiased