Transcript Clicker_chapter8.ppt

Producing Data: Sampling
BPS chapter 8
© 2006 W.H. Freeman and Company
Sampling
In 1993, presidential candidate Ross Perot appeared on television to
voice his opinions on government reform. To gauge public opinion,
Perot urged viewers to fill out the survey appearing in that week’s
issue of TV Guide. Of the approximately 1.4 million respondents,
98% agreed with Ross Perot’s platform on health care reform.
What type of sampling method was used?
a)
b)
c)
d)
e)
Convenience sample
Voluntary response sample
Simple random sample
Stratified sample
Multistage sample
Sampling (answer)
In 1993, presidential candidate Ross Perot appeared on television to
voice his opinions on government reform. To gauge public opinion,
Perot urged viewers to fill out the survey appearing in that week’s
issue of TV Guide. Of the approximately 1.4 million respondents,
98% agreed with Ross Perot’s platform on health care reform.
What type of sampling method was used?
a)
b)
c)
d)
e)
Convenience sample
Voluntary response sample
Simple random sample
Stratified sample
Multistage sample
Sampling
Which of the following is NOT a type of probability sample?
a)
b)
c)
d)
e)
Voluntary response sample
Simple random sample
Stratified sample
Multistage sample
All are probability samples.
Sampling (answer)
Which of the following is NOT a type of probability sample?
a)
b)
c)
d)
e)
Voluntary response sample
Simple random sample
Stratified sample
Multistage sample
All are probability samples.
Sampling
Suppose you want to estimate the proportion of students at a large
university that approve of the new health care bill. You take an SRS
of 200 of the 25,000 undergraduate students and an SRS of the 100
of the 5,000 graduate students. This overall sample is a
a)
b)
c)
d)
e)
Voluntary response sample
Simple random sample
Stratified sample
Multistage sample
None of the above
Sampling (answer)
Suppose you want to estimate the proportion of students at a large
university that approve of the new health care bill. You take an SRS
of 200 of the 25,000 undergraduate students and an SRS of the 100
of the 5,000 graduate students. This overall sample is a
a)
b)
c)
d)
e)
Voluntary response sample
Simple random sample
Stratified sample
Multistage sample
None of the above
Selecting a sample
Select an SRS of 5 packages of peanuts form a case containing 30
packages of peanuts. Label the packages 01 to 30 and use the line
from the table of random digits shown below.
Your SRS contains the packages of peanuts labeled
a)
b)
c)
d)
e)
14, 44, 45, 49, 92
14, 26, 05, 14, 24
14, 45, 92, 60, 56
14, 03, 10, 22, 06
None of the above
Selecting a sample (answer)
Select an SRS of 5 packages of peanuts form a case containing 30
packages of peanuts. Label the packages 01 to 30 and use the line
from the table of random digits shown below.
Your SRS contains the packages of peanuts labeled
a)
b)
c)
d)
e)
14, 44, 45, 49, 92
14, 26, 05, 14, 24
14, 45, 92, 60, 56
14, 03, 10, 22, 06
None of the above
Sampling
Which of the following sampling schemes describes a multistage
sample of 200 undergraduate students at a large university?
a)
b)
c)
Obtain a list of the undergraduate students at the large university;
assign consecutive numbers to the students on the list; use a
random number table to select 200 university students.
Obtain a list of all freshmen, sophomores, juniors, and seniors; use
a random number table to randomly select 50 students from each
class.
Randomly select 10 colleges; within each college, randomly select 5
majors; from each of the selected majors randomly select 4
undergraduate students.
Sampling (answer)
Which of the following sampling schemes describes a multistage
sample of 200 undergraduate students at a large university?
a)
b)
c)
Obtain a list of the undergraduate students at the large university;
assign consecutive numbers to the students on the list; use a
random number table to select 200 university students.
Obtain a list of all freshmen, sophomores, juniors, and seniors; use
a random number table to randomly select 50 students from each
class.
Randomly select 10 colleges; within each college, randomly
select 5 majors; from each of the selected majors randomly
select 4 undergraduate students.
Bias
A Gallup poll sponsored by the disposable diaper industry asked “It is
estimated that disposable diapers account for less than 2% of the
trash in today’s landfills. In contrast, beverage containers, thirdclass mail, and yard waste are estimated to account for about 21%
of the trash in landfills. Given this, in your opinion, would it be fair to
ban disposable diapers?”
Which type of bias does this poll suffer from?
a)
b)
c)
d)
e)
Under-coverage bias
Non-response bias
Response bias
Question wording bias
Interviewer bias
Bias (answer)
A Gallup poll sponsored by the disposable diaper industry asked “It is
estimated that disposable diapers account for less than 2% of the
trash in today’s landfills. In contrast, beverage containers, thirdclass mail, and yard waste are estimated to account for about 21%
of the trash in landfills. Given this, in your opinion, would it be fair to
ban disposable diapers?”
Which type of bias does this poll suffer from?
a)
b)
c)
d)
e)
Under-coverage bias
Non-response bias
Response bias
Question wording bias
Interviewer bias
Bias
True or false: Bias can occur in both probability and non-probability
samples.
a)
b)
True
False
Bias (answer)
True or false: Bias can occur in both probability and non-probability
samples.
a)
b)
True
False
Bias
Using a local telephone book to select a simple random sample could
introduce what type of bias?
a)
b)
c)
d)
e)
Under-coverage bias
Non-response bias
Response bias
Question wording bias
Interviewer bias
Bias (answer)
Using a local telephone book to select a simple random sample could
introduce what type of bias?
a)
b)
c)
d)
e)
Under-coverage bias
Non-response bias
Response bias
Question wording bias
Interviewer bias
Probability samples
An important characteristic of probability samples is that
a)
b)
c)
d)
Results of one sample are usually the same as the results for the
entire population.
Results of one sample are usually the same as the results for
another sample of the same size.
Principles of chance apply and the size of error due to sampling is
measurable.
Smaller samples give more accurate results than larger samples.
Probability samples (answer)
An important characteristic of probability samples is that
a)
b)
c)
d)
Results of one sample are usually the same as the results for the
entire population.
Results of one sample are usually the same as the results for
another sample of the same size.
Principles of chance apply and the size of error due to
sampling is measurable.
Smaller samples give more accurate results than larger samples.
Bias
If people tend to respond differently to a question depending on
whether the interviewer is male or female, which type of bias is
present?
a)
b)
c)
d)
e)
Under-coverage bias
Non-response bias
Response bias
Question wording bias
Interviewer bias
Bias (answer)
If people tend to respond differently to a question depending on
whether the interviewer is male or female, which type of bias is
present?
a)
b)
c)
d)
e)
Under-coverage bias
Non-response bias
Response bias
Question wording bias
Interviewer bias