Page 196 - Math Course 3 (Book 2)
P. 196
Sampling and Bias
MO. 12 - L4b Key Concept
Recognizing a Biased Sample
Biased Samples
Type Convenience sample
Vocabulary A-Z Definition A convenience sample includes
Let us learn some vocabulary members of a population who are
easily accessed.
Example To check spoilage, a produce worker
biased sample selects 10 apples from the top of the
bin. The 10 apples are unlikely to
Random samples are unbiased. In a biased sample, represents all of the apples in the bin.
one or more parts of a population are favored over
others. Type Voluntary Response sample
Every 2 minutes, an Asian person is searched at Definition A voluntary response sample involves
the airport. only those who want to participate in
the sampling.
Example A radio call-in show record that 75% of
its 40 callers voiced negative opinions
about a local football team. Those 40
callers are unlikely to represents the
entire local population.
Biased Sample Unbiased Sample
Volunteer caller are more likely to have
strong opinions and are typically more
negative than the entire population.
convenience sample
A convenience sample includes members of a
population who are easily accessed.
Let’s Begin
To check spoilage, a produce
worker selects 10 apples from
the top of the bin. The 10 apples
are unlikely to represents all of Identify Sample as Biased or Unbiased
the apples in the bin.
Example
voluntary response sample
A voluntary response sample involves only those STUDENT COUNCIL
who want to participate in the sampling. The student council surveys the students in one
classroom to decide the theme for the spring
A radio call-in show record that 75% of its 40 dance.
callers voiced negative opinions about a local
football team. Those 40 callers are unlikely to Identify the sample as biased or unbiased. Explain
represents the entire local population. your reasoning.
Volunteer caller are more likely to have strong The sample includes only students in one class-
opinions and are typically more negative than the room.
entire population.
Answer The sample is biased.
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