Chapter.8 Populations, Samples, And Probability Test Bank - Statistics 11th Edition Test Questions and Answer Key by Robert S. Witte. DOCX document preview.
MULTIPLE‑CHOICE TEST ITEMS
CHAPTER 8
POPULATIONS, SAMPLES, AND PROBABILITY
8.1 In inferential statistics the likelihood of erroneous generalizations can be
a) eliminated.
b) controlled.
c) ignored.
d) bypassed.
8.2 You might choose to survey an entire population if the population is
a) small.
b) accessible.
c) real.
d) important.
8.3 It would be impossible to survey a population consisting of all
a) U.S. citizens registered to vote in the most recent presidential election.
b) major league baseball players active during the last season.
c) possible tosses of a particular coin.
d) currently hospitalized patients in the state of Pennsylvania.
8.4 A real population is one in which all observations are
a) living people.
b) physical.
c) accessible.
d) substantial.
8.5 Pollsters conduct surveys based on
a) real populations.
b) hypothetical populations.
c) either real or hypothetical populations.
d) neither real nor hypothetical populations.
8.6 Subjects in experiments are viewed as samples from populations that are
a) very large.
b) undefined.
c) real.
d) hypothetical.
8.7 Strictly speaking, any generalization in inferential statistics should be limited to the
a) sample.
b) population.
c) real population that has been sampled.
d) hypothetical population that has been sampled.
8.8 Generalizations to hypothetical populations should be viewed as
a) inappropriate.
b) provisional.
c) erroneous.
d) invalid.
8.9 Typically, sample size is
a) large.
b) less than 100.
c) small relative to the population size.
d) less than one‑hundredth of 1 percent of the population size.
8.10 Whether or not a sample is random depends entirely on the
a) outcome.
b) accuracy of the outcome.
c) size of the sample.
d) selection process.
8.11 The optimal sample size for any situation
a) equals a certain percent of the population size.
b) equals some number between 10 and 100.
c) depends on the population size.
d) depends on answers to a number of questions.
8.12 A sample is random if the selection process generates a set of observations that is
a) haphazard.
b) nonsystematic.
c) representative.
d) none of the above
8.13 When taking a random sample of ten students from a large class that contains about equal numbers of males and females, you obtain nine males and only one female. This particular outcome is
a) impossible.
b) unlikely, but possible.
c) proof that the sample isn't random.
d) just as likely as any other outcome, such as six males and four females.
8.14 Tables of random numbers are created by
a) pollsters.
b) investigators.
c) computers.
d) flips of a coin.
8.15 If you were attempting to take a random sample from a real population consisting of 6,000 people, you would use random numbers having
a) one digit.
b) two digits.
c) three digits.
d) four digits.
8.16 The tables of random numbers should be entered at
a) some haphazardly determined point.
b) some haphazardly determined point on the first page.
c) the upper left‑hand corner of the first page.
d) the middle of the tables.
8.17 When using tables of random numbers to obtain a random sample from a city telephone directory, a six‑digit random number, such as 379456, most likely would identify the
a) name listed in the 379,456th position of the directory.
b) name on page 379 and line 456.
c) telephone number having 379456 as its last six digits.
d) telephone number containing the digits 379456 in any order.
8.18 In experiments, subjects are assigned
a) casually.
b) haphazardly.
c) impartially.
d) randomly.
8.19 The random assignment of subjects to groups in an experiment provides a basis for deciding whether an observed mean difference is
a) large or small.
b) real or transitory.
c) true or false.
d) important or unimportant.
8.20 The random assignment of subjects to two or more experimental groups tends to produce groups that are
a) equal at the outset of the experiment.
b) similar at the outset of the experiment.
c) noticeably different at the outset of the experiment.
d) noticeably different at the end of the experiment.
8.21 When using tables of random numbers to assign subjects to either experimental condition A or experimental condition B, the best rule would be to
a) assign A if number is odd; B if number is even.
b) assign A if number is odd; B if number is even, with alternate assignments to the condition with fewer subjects.
c) alternate assignments to A and B.
d) assign first half to A and the second half to B.
8.22 In an experiment, it's highly desirable that subjects be assigned to the experimental and control groups
a) in equal numbers.
b) without regard to group size.
c) as soon as possible.
d) according to when they actually arrive in the lab.
8.23 Whether a survey or an experiment, a well‑designed investigation always uses some form of
a) numerical measurement.
b) generalization.
c) randomization.
d) control.
8.24 If subjects are being sampled from a real population, then the study is best described as
a) a survey.
b) a census.
c) an experiment.
d) an investigation.
8.25 A random selection of registered voters within the state of Nevada guarantees that
a) at least some registered voters will be selected from Reno.
b) at least some registered voters will be selected from each county.
c) all registered voters have an equal chance of being selected.
d) all registered voters will be adequately represented.
8.26 On the basis of more than 90,000 letters, a syndicated columnist reports that a majority of American parents regret having children. A reasonable evaluation of this finding, with respect to the population of American parents, is that it's
a) representative because of the huge sample size.
b) representative because respondents were volunteers.
c) not representative because of the relatively small sample size.
d) not representative because respondents were self‑selected.
8.27 Six subjects are to be assigned randomly to either group A or group B as they arrive, one at a time, to participate in an experiment. Your assignment rule specifies that group A is assigned if the first digit of the random number is odd, and otherwise group B is assigned. In order to ensure equal numbers of subjects in both groups, alternate subjects are automatically assigned to the group having the smaller number of subjects. For the following list of random numbers:
74029
44178
11664
48324
69074
09188
indicate the correct assignments for the six subjects
a) ABBAAB
b) ABBABA
c) ABABAB
d) AAABBB
8.28 Probability refers to the
a) number of times some event will occur.
b) percent of times some event will occur.
c) proportion of times some event will occur.
d) all of the above
8.29 The probability of an outcome can be determined by
a) speculation.
b) observation.
c) speculation and observation.
d) none of the above
8.30 If a long string of coin tosses reveals that heads occur more often than tails for a particular coin, then the probability of heads for that coin is
a) greater than 1/2.
b) still equal to 1/2.
c) smaller than 1/2.
d) unknowable.
8.31 On the assumption that voters do not prefer either of four candidates, the probability of a vote for one of these candidates, say candidate A, equals
a) 1/2.
b) 1/3.
c) 1/4.
d) none of the above
8.32 If an outcome has a probability of zero, the occurrence of that outcome is
a) impossible.
b) remarkable.
c) unlikely.
d) certain.
8.33 An entire set of probabilities always sums to
a) some non-negative number.
b) some number between zero and one.
c) some positive number.
d) one.
8.34 A psychotherapist estimates that, during the last ten years, about 800 of her 1,000 patients demonstrated a dramatic improvement in mental health. Therefore, the estimated probability of a dramatic improvement among her new patients is
a) .08
b) .80
c) 8 out of 10
d) 800
8.35 Two outcomes are mutually exclusive if
a) they can't occur together.
b) the occurrence of one outcome has no effect on the probability that the other outcome will occur.
c) their two probabilities sum to one.
d) their probability of occurring together is greater than zero.
8.36 Assume that in a statistics class the probability of receiving a grade of A equals .30 and the probability of receiving a grade of B equals .30. The probability that a randomly selected student from this class will receive either an A or a B equals
a) .09
b) .30
c) .60
d) .90
8.37 Assume that in a statistics class the probability of receiving a grade of A equals .30 and the probability of receiving a grade of B equals .30. The probability that a randomly selected student from this class will receive a grade other than an A or a B equals
a) .09
b) .36
c) .40
d) .91
8.38 Consider using the addition rule when simple outcomes are connected by the word
a) and.
b) if.
c) but.
d) or.
8.39 If outcomes aren't mutually exclusive, the addition rule given in the book yields an answer that is
a) correct.
b) too large because of the overlap between outcomes.
c) too small because of the separation between outcomes.
d) either inflated or deflated, depending on circumstances.
8.40 Consider using the multiplication rule when simple outcomes are connected by the word
a) and.
b) if.
c) but.
d) or.
8.41 If outcomes are dependent, the multiplication rule given in the book yields an answer that is
a) correct.
b) too large.
c) too small.
d) either too large or too small, depending on circumstances.
8.42 The probability that any offspring of alcoholic parents will be alcoholic equals .20. Therefore, assuming independent outcomes, the probability that two children of alcoholic parents both will be alcoholic equals
a) .04
b) .10
c) .20
d) .40
8.43 Since the probability that a new marriage will end in divorce varies depending on whether either of the newly-weds has a divorce record, these two outcomes (the fate of the new marriage and the newly-weds' divorce record) are
a) dependent.
b) independent.
c) mutually exclusive.
d) non-mutually exclusive.
8.44 If scores on two successive statistics exams are dependent, the probability of your getting an A on both the first exam (A1) and the second exam (A2) equals
a) the probability of A1 multiplied by the conditional probability of A2.
b) the probability of A1 multiplied by the conditional probability of A2, given A1.
c) the probability of A2 multiplied by the conditional probability of A2, given A1.
d) the conditional probability of A1 multiplied by the conditional probability of A2.
8.45 Given that scores on two successive statistics exams are dependent, it most likely that the conditional probability of getting an A on the second exam, given an A on the first exam, is ________________ than the unconditional probability of getting an A on the second exam.
a) no different
b) larger
c) smaller
d) different
8.46 Statisticians often wish to determine whether random outcomes can be viewed as either
a) true or false.
b) real or theoretical.
c) biased or unbiased.
d) common or rare.
8.47 If the probability of some outcome is small, that outcome is viewed as
a) common.
b) rare.
c) real.
d) impossible.
8.48 If the probability equals .01 that any randomly selected person from the general population has an IQ of 145 or above, what's the probability that three randomly selected people all will have IQs of 145 or above?
a) .01 + .01
b) .01 + .01 + .01
c) (.01)(.01)
d) (.01)(.01)(.01)
8.49 Given that the probability equals .025 that a randomly selected z score (from the standard normal table) deviates above 1.96, the probability that a z score deviates either above 1.96 or below ‑1.96 equals
a) .025
b) .025 + .025
c) (.025)(.025)
d) .25
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Statistics 11th Edition Test Questions and Answer Key
By Robert S. Witte