USING R FOR INTRODUCTORY STATISTICS
2ND EDITION VERZANI SOLUTIONS
MANUAL ACTUAL EXAM 2026 FULL
QUESTIONS AND CORRECT ANSWERS
GRADED A+
⩥ Source of data: In concluding a statistical study, why is it important to
consider the source of the data? Answer: (A) It's important to determine
if the source of the data would be impacted favorably by the conclusions
of the data. If so the conclusion is likely bias and invalid.
⩥ Voluntary Response Sample:What is a voluntary response sample, and
why is such a sample generally not suitable for a statistical study?
Answer: (A) A voluntary response sample is a sample in which the
subjects themselves decide whether to be included in the study. A
voluntary response sample is generally not suitable for a statistical study
because the sample may have a bias resulting from participation by those
with a special interest in the topic being studied.
⩥ Correlation and Causation: What is meant by the statement that
"correlation does not imply causation"? Answer: (A) Correlation is an
association between two variables. For example, a statistical study may
justify the statement that there is a correlation between the number of
cigarettes smoked and pulse rate, but it would not justify a statement that
the number of cigarettes smoked causes a person's pulse rate to change.
,Statements about causality can be justified by physical evidence, not by
statistical analysis.
⩥ Determine if results have statistical and practical significance: In a
study of the Marisa Waite diet, four subjects lost an average of 45
pounds. It is found that there is about a 30% chance of getting such
results with a diet that has no effect. Answer: Because there is a 30%
chance of getting such results with a diet that has no effect, it does not
appear to have a statistical significance, but the average loss of 45
pounds does appear to have practical significance.
⩥ Determine if results have statistical and practical significance: In a
study of the Gender Aide method of gender selection, 1000 user of the
method gave birth to 540 boys and 460 girls. There is about a 1% chance
that such extreme results would occur if the method had no effect.
Answer: Because there is a 1% chance that such results would occur if
the method had no effect, is appears to have statistical significance, but it
does not appear to have practical significance.
⩥ When making random guesses for difficult multiple-choice test
questions with possible answers of a, b, c, d, and e, we expect to get
about 20% of the answers correct. The Ashton Prep Program claims to
have developed a better method of guessing. In a test of that program,
guesses were made for 100 answers, and 23 were found to be correct.
There is a 23% chance of getting such results if the program has no
effect. Answer: Because there is a 23% chance of getting such results if
the program has no effect, it does not appear to have statistical
, significance. Because the success rate of 23% is not that much better
than the 20% rate, it does not appear to have practical significance.
⩥ Most people have IQ scores between 70 and 130. For $32, you can
purchase a computer program from Highiqpro.com that is claimed to
increase your IQ score by 10 to 20 points. The program claims to be "the
only proven IQ increasing software in the brain training market," but the
author of your text could find no data supporting that claim, so let's
suppose that these results were obtained: In a study of 12 subjects using
the program, the average increase in IQ is 3 IQ points. There is a 25%
chance of getting such results if the program has no effect. Answer:
Because there is a 25% chance of getting such results if the program has
no effect, it does not appear to have statistical significance. Because the
average increase in IQ from the study was only 3 IQ points, while the
program claimed to improve your IQ by 10 to 20 points, there does not
appear to have practical significance.
⩥ The associated press provided an article with a headline stating that
ATV accidents killed 704 people in the last year. The article noted that
this is a new record high and compares it to the 617 ATV deaths the year
before that. Other data about the frequency or injuries were included.
What important values was not included? Why is it important? Answer:
(A)Without knowing anything about the number of ATV's in use, or the
number of ATV drivers, or the amount of ATV usage, the number of 740
fatal accidents has no context. Some information should be given so that
the reader can understand the rate of ATV fatalities.
2ND EDITION VERZANI SOLUTIONS
MANUAL ACTUAL EXAM 2026 FULL
QUESTIONS AND CORRECT ANSWERS
GRADED A+
⩥ Source of data: In concluding a statistical study, why is it important to
consider the source of the data? Answer: (A) It's important to determine
if the source of the data would be impacted favorably by the conclusions
of the data. If so the conclusion is likely bias and invalid.
⩥ Voluntary Response Sample:What is a voluntary response sample, and
why is such a sample generally not suitable for a statistical study?
Answer: (A) A voluntary response sample is a sample in which the
subjects themselves decide whether to be included in the study. A
voluntary response sample is generally not suitable for a statistical study
because the sample may have a bias resulting from participation by those
with a special interest in the topic being studied.
⩥ Correlation and Causation: What is meant by the statement that
"correlation does not imply causation"? Answer: (A) Correlation is an
association between two variables. For example, a statistical study may
justify the statement that there is a correlation between the number of
cigarettes smoked and pulse rate, but it would not justify a statement that
the number of cigarettes smoked causes a person's pulse rate to change.
,Statements about causality can be justified by physical evidence, not by
statistical analysis.
⩥ Determine if results have statistical and practical significance: In a
study of the Marisa Waite diet, four subjects lost an average of 45
pounds. It is found that there is about a 30% chance of getting such
results with a diet that has no effect. Answer: Because there is a 30%
chance of getting such results with a diet that has no effect, it does not
appear to have a statistical significance, but the average loss of 45
pounds does appear to have practical significance.
⩥ Determine if results have statistical and practical significance: In a
study of the Gender Aide method of gender selection, 1000 user of the
method gave birth to 540 boys and 460 girls. There is about a 1% chance
that such extreme results would occur if the method had no effect.
Answer: Because there is a 1% chance that such results would occur if
the method had no effect, is appears to have statistical significance, but it
does not appear to have practical significance.
⩥ When making random guesses for difficult multiple-choice test
questions with possible answers of a, b, c, d, and e, we expect to get
about 20% of the answers correct. The Ashton Prep Program claims to
have developed a better method of guessing. In a test of that program,
guesses were made for 100 answers, and 23 were found to be correct.
There is a 23% chance of getting such results if the program has no
effect. Answer: Because there is a 23% chance of getting such results if
the program has no effect, it does not appear to have statistical
, significance. Because the success rate of 23% is not that much better
than the 20% rate, it does not appear to have practical significance.
⩥ Most people have IQ scores between 70 and 130. For $32, you can
purchase a computer program from Highiqpro.com that is claimed to
increase your IQ score by 10 to 20 points. The program claims to be "the
only proven IQ increasing software in the brain training market," but the
author of your text could find no data supporting that claim, so let's
suppose that these results were obtained: In a study of 12 subjects using
the program, the average increase in IQ is 3 IQ points. There is a 25%
chance of getting such results if the program has no effect. Answer:
Because there is a 25% chance of getting such results if the program has
no effect, it does not appear to have statistical significance. Because the
average increase in IQ from the study was only 3 IQ points, while the
program claimed to improve your IQ by 10 to 20 points, there does not
appear to have practical significance.
⩥ The associated press provided an article with a headline stating that
ATV accidents killed 704 people in the last year. The article noted that
this is a new record high and compares it to the 617 ATV deaths the year
before that. Other data about the frequency or injuries were included.
What important values was not included? Why is it important? Answer:
(A)Without knowing anything about the number of ATV's in use, or the
number of ATV drivers, or the amount of ATV usage, the number of 740
fatal accidents has no context. Some information should be given so that
the reader can understand the rate of ATV fatalities.
