Statistics Chapter 1 Practice Test
Questions And Answers Verified 100%
Correct
Was this a controlled experiment or an observational study? Explain why. From studies
like these, can we conclude a cause-and-effect relationship between the drug type and
the survival percentage? Why or why not? - answer This is a controlled experiment
because the researchers randomly determined the groups. We can conclude a
causeand-effect relationship because the women were randomly assigned to the
treatment and control groups, which controls for other variables.
A study was done to see whether a smaller dose of flu vaccine could be used
successfully. In this study, the usual amount of vaccine was injected into half the
patients, and the other half of the patients had only a small amount of vaccine injected.
The response was measured by looking at the production of antibodies. In the end, the
lower dose of vaccine was just as effective as a higher dose for those under 65 years
old. What more do we need to know to be able to conclude that the lower dose of
vaccine was equally effective at preventing the flu for those under 65?
A. This is a controlled experiment and causation cannot be inferred.
B. The sample size must be at least 500 to ensure the sample size is large enough to
infer causation.
C. This is an observational study and causation cannot be inferred.
D. The patients need to be randomly assigned the full or lower dose. Without
randomization there could be bias, however, with randomization we can infer
causation. - answer D. The patients need to be randomly assigned the full or lower
dose. Without randomization there could be bias, however, with randomization we
can infer causation. A study looked at the effects of light on female mice. Fifty mice
were randomly assigned to a regimen of 12 hours of light and 12 hours of dark (LD),
while another fifty mice were assigned to 24 hours of light (LL). Researchers
observed the mice for two years. Three of the LD mice and 15 of the LL mice
developed tumors.
Determine the percentage of mice that developed tumors from each group (LL and LD).
Compare them and comment - answer In the LD mice, 6% developed tumors. In the LL
mice, 30% developed tumors. The LD mice developed tumors at a lower rate than the
LL mice.
, A study looked at the effects of light on female mice. Fifty mice were randomly assigned
to a regimen of 12 hours of light and 12 hours of dark (LD), while another fifty mice were
assigned to 24 hours of light (LL). Researchers observed the mice for two years. Three
of the LD mice and 15 of the LL mice developed tumors.
Was this a controlled experiment or an observational study? How do you know? -
answer This was a controlled experiment because there were two groups that were
assigned by the researchers.
A study looked at the effects of light on female mice. Fifty mice were randomly assigned
to a regimen of 12 hours of light and 12 hours of dark (LD), while another fifty mice were
assigned to 24 hours of light (LL). Researchers observed the mice for two years. Three
of the LD mice and 15 of the LL mice developed tumors.
Can we conclude that light for 24 hours a day causes an increase in tumors in mice?
Why or why not? - answer Because it was a controlled experiment, it can be concluded
that light for 24 hours a day causes an increase in tumors in mice.
Questions about causality are usually phrased in the form of ___ questions. - answer
Questions about causality are usually phrased in the form of "What if...?" questions.
The outcome variable in a question about causality is also referred to as what? -
answer The response variable
In an experiment studying the association between a treatment variable and an
outcome variable, the group of people who do NOT receive the treatment are called
what? - answer The control group
Of the following, which is the only method of data collection suitable for making
conclusions about causal relationships? - answer Controlled experiments Which of the
following is an identifying mark of an observational study? - answer Subjects in the
study are put into the treatment group or the control group either by their own actions or
by the decision of someone not involved in the research study. A difference between
two groups in an observational study that can explain why the outcomes were very
different between the groups is called what? - answer A confounding variable
Which of the following is a reason we can never draw cause-and-effect conclusions
from observational studies? - answer Potential confounding variables may explain the
differences between groups rather than the treatment variable.
Why is random assignment used to assign people to treatment groups and control
groups in a controlled experiment? - answer To make the groups as similar as possible,
minimizing bias.
Which of the following is NOT one of the criteria for the "gold standard" for experiments?
- answer Equal sample sizes for control and treatment group
The study of statistics rests on what two major concepts? - answer Variation and data
The circles shown to the right are similar, but not exactly the same. This is an example
of _______. - answer The circles shown to the right are similar, but not exactly the
same. This is an example of variation.
Questions And Answers Verified 100%
Correct
Was this a controlled experiment or an observational study? Explain why. From studies
like these, can we conclude a cause-and-effect relationship between the drug type and
the survival percentage? Why or why not? - answer This is a controlled experiment
because the researchers randomly determined the groups. We can conclude a
causeand-effect relationship because the women were randomly assigned to the
treatment and control groups, which controls for other variables.
A study was done to see whether a smaller dose of flu vaccine could be used
successfully. In this study, the usual amount of vaccine was injected into half the
patients, and the other half of the patients had only a small amount of vaccine injected.
The response was measured by looking at the production of antibodies. In the end, the
lower dose of vaccine was just as effective as a higher dose for those under 65 years
old. What more do we need to know to be able to conclude that the lower dose of
vaccine was equally effective at preventing the flu for those under 65?
A. This is a controlled experiment and causation cannot be inferred.
B. The sample size must be at least 500 to ensure the sample size is large enough to
infer causation.
C. This is an observational study and causation cannot be inferred.
D. The patients need to be randomly assigned the full or lower dose. Without
randomization there could be bias, however, with randomization we can infer
causation. - answer D. The patients need to be randomly assigned the full or lower
dose. Without randomization there could be bias, however, with randomization we
can infer causation. A study looked at the effects of light on female mice. Fifty mice
were randomly assigned to a regimen of 12 hours of light and 12 hours of dark (LD),
while another fifty mice were assigned to 24 hours of light (LL). Researchers
observed the mice for two years. Three of the LD mice and 15 of the LL mice
developed tumors.
Determine the percentage of mice that developed tumors from each group (LL and LD).
Compare them and comment - answer In the LD mice, 6% developed tumors. In the LL
mice, 30% developed tumors. The LD mice developed tumors at a lower rate than the
LL mice.
, A study looked at the effects of light on female mice. Fifty mice were randomly assigned
to a regimen of 12 hours of light and 12 hours of dark (LD), while another fifty mice were
assigned to 24 hours of light (LL). Researchers observed the mice for two years. Three
of the LD mice and 15 of the LL mice developed tumors.
Was this a controlled experiment or an observational study? How do you know? -
answer This was a controlled experiment because there were two groups that were
assigned by the researchers.
A study looked at the effects of light on female mice. Fifty mice were randomly assigned
to a regimen of 12 hours of light and 12 hours of dark (LD), while another fifty mice were
assigned to 24 hours of light (LL). Researchers observed the mice for two years. Three
of the LD mice and 15 of the LL mice developed tumors.
Can we conclude that light for 24 hours a day causes an increase in tumors in mice?
Why or why not? - answer Because it was a controlled experiment, it can be concluded
that light for 24 hours a day causes an increase in tumors in mice.
Questions about causality are usually phrased in the form of ___ questions. - answer
Questions about causality are usually phrased in the form of "What if...?" questions.
The outcome variable in a question about causality is also referred to as what? -
answer The response variable
In an experiment studying the association between a treatment variable and an
outcome variable, the group of people who do NOT receive the treatment are called
what? - answer The control group
Of the following, which is the only method of data collection suitable for making
conclusions about causal relationships? - answer Controlled experiments Which of the
following is an identifying mark of an observational study? - answer Subjects in the
study are put into the treatment group or the control group either by their own actions or
by the decision of someone not involved in the research study. A difference between
two groups in an observational study that can explain why the outcomes were very
different between the groups is called what? - answer A confounding variable
Which of the following is a reason we can never draw cause-and-effect conclusions
from observational studies? - answer Potential confounding variables may explain the
differences between groups rather than the treatment variable.
Why is random assignment used to assign people to treatment groups and control
groups in a controlled experiment? - answer To make the groups as similar as possible,
minimizing bias.
Which of the following is NOT one of the criteria for the "gold standard" for experiments?
- answer Equal sample sizes for control and treatment group
The study of statistics rests on what two major concepts? - answer Variation and data
The circles shown to the right are similar, but not exactly the same. This is an example
of _______. - answer The circles shown to the right are similar, but not exactly the
same. This is an example of variation.
