YMS Chapter 5: Producing Data
Q1. The difference between an observational study and an experiment is that in the first,
the explanatory variable is observed and measured, whereas in an experiment, the
explanatory variable is ____.
Q2. When there is a jobs program for welfare recipients, and you simply observe that
those who voluntarily take part in the program do better than those who don’t, what’s the
problem with inferring that the program causes better results?
Q3. The entire group of individuals we want information about is called the _____.
Q4. The subset of the population we actually examine in order to gather information is
called the ______.
Q5. Studying the whole population by attempting to contact every individual is called
conducting a ______.
Q6. Studying a population by taking a subset of it in order to generalize to the whole
population is called _____.
Q7. The method used for selecting the sample from the population is called the ____ of
sampling.
Q8. If a radio station invites anyone who wants to call and give an opinion on a question,
the set of people thus obtained is called a _____ response sample.
Q9. If the researcher enrolls a group of people in the study on the basis of how easy it is
to contact them and get them to enroll, that method of sampling is called ______
sampling.
Q10. The systematic error introduced when the sample is very different from the
population is called ____.
Q11. If a conservative radio commentator polls his listeners, and a liberal commentator
polls her listeners, both polls are likely to be biased as methods of ascertaining the
sentiment of the country, because _______.
Q12. A SRS, or simple random sample, is a subset of n individuals from a population,
chosen in such a way that ____.
Q13. True or false: if every individual in the population has an equal chance of being
included in the sample, the sample is a simple random sample.
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View Full DocumentQ14. Suppose I take the numbers 1, 2, 3, and 4, and write them on identical pieces of
paper, put them into a hat and mix them thoroughly, and draw out two numbers. Is this a
simple random sample of the 4 numbers?
Q15. Suppose I take the numbers 1, 2, 3, and 4. First I take the numbers 1 and 2 and put
them into a hat, and choose one of them. Then I take the numbers 3 and 4 and put them
into a hat and choose one of them. For each of the numbers 1, 2, 3, and 4, what is the
probability that this number will end up in the sample?
Q16. Is it possible that the subset {1,2} would be chosen for our sample using the
sampling method just mentioned (that is, pick randomly from 1 and 2, then pick
randomly from 3 and 4)?
Q17. So the sampling method just mentioned is one where each individual has equal
probability of being chosen, but each subset is not equally likely to be chosen; thus the
sample obtained is, or is not, a simple random sample?
Q18. In a table of random digits, each triple of digits is equally likely to be any of the
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 Spring '07
 Molina
 Statistics, researcher, Simple random sample

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