Final Statistics Exam Questions With Accurate Solutions.
When thinking about p-values...
The probability of missing an effect entirely (ie. a false negative finding) best
represents what type of error?
A. Type I (alpha)
B. Type II (beta)
C. Statistical powerD. Statistical significance - accurate answers-b. Type II
(beta)
The p-value is the probability that you would see that you saw in your sample,
or something even more extreme, assuming which of the following statements
is true?
A. When there is no difference between treatments
B. When the null hypothesis is true
C. When what you observed could have arisen solely by chance
D. All of the above - accurate answers-D. All of the above
Trivial effects may achieve statistical significance if the ______ is large enough.
A. Sample size
B. Z-score
C. P-value
D. Confidence interval - accurate answers-Sample size
If you fail to reject the null hypothesis, that is not proof of "no effect."
a. true
b. false - accurate answers-True
Which of the following p-values would be considered "statistically significant"
in most medical studies?
A. 0.058
B. 0.0058
C. 0.58D. None of the above would be considered statistically significant -
accurate answers-<0.05
0.0058
,A study with a large sample is broken down into many subgroups and each
individual in each subgroup is then analyzed before and after an exposure.
Testing the same data in many ways, such as in this example, may lead to
statistical significance about 1 in every 20 tests, though the significance may
be a change finding and entirely meaningless. This is an example of which type
of problem with p-values?
A. Error
B. Clinical vs statistical significance
C. Multiple testing
d. comparing p-values - accurate answers-C. Multiple testing
We are testing the effectiveness of a new vaccine. Our null hypothesis is that
the vaccine does not work to prevent the disease in question. If we conclude
that the vaccine works when in reality the null hypothesis is true, what type of
error have we made?
A. Type I (alpha)
B. Type II (beta)
C. Type III (statistical power)
D. We did not make an error - accurate answers-A. Type I (alpha)
T/F
You can prove the null hypothesis - accurate answers-False
Study designs often make comparisons within a group (ie. Did this group
compare itself at baseline?) and between multiple groups (ie, Did group A
improve more than group b?). For randomized, controlled trials ONLY effects
using this type of comparison are truly relevant and should be reported as the
primary outcome.
A. Within group effects
B. Between group effects
C. Both comparisons can be relevant D. Neither comparison are truly relevant
- accurate answers-Between-group effects
P-values depend on effect size, sample size, and variability. Which of the
following represents the correct relationship between these variables and
how then can affect p-values?
A. High effect size, low p-value
B. High sample size, low p-value
C. High variability, high p-value
, D. All of the above are correct - accurate answers-D. All of the above are
correct
Six women in study on lipid lowering agents are aged 52, 55, 56, 58, 59, and
92. What is the median? - accurate answers-57
The statistic that provides the average distance from the mean, and that is one
of the most important measures of variability is? - accurate answers-Standard
Deviation
When calculating a mean, we lose a degree of freedom. This becomes
important when we go to calculate: - accurate answers-standard deviation
Solve this factorial: 5!/2!3!: - accurate answers-10
Five women in a study on lipid lowering agents are aged 55,59, 52, 58, and 56.
Calculate the mean age: - accurate answers-56
The box plot represents what portion of data: - accurate answers-IQR: 50% of
ordered values
When thinking about a normal bell curve, what percentage of you data will fall
within 2 standard deviations of the mean? - accurate answers-95%
What is the equation of a line? - accurate answers-y=mx+b
Blood types is an example of what type of data? - accurate answers-
Categorical: nominal
Occasionally, it makes more sense to compare ____ when looking at skewed
data because it is unaffected by outliers unlike any other measurements -
accurate answers-Median
What's the correct way to interpret this risk ratio? Those who take low dose
aspirin regularly have 0.58 times the risk of myocardial infarction compared
to those who do not take aspirin. - accurate answers-Aspirin has a protective
effect (a decreased incidence) with lower risk of MI
When thinking about p-values...
The probability of missing an effect entirely (ie. a false negative finding) best
represents what type of error?
A. Type I (alpha)
B. Type II (beta)
C. Statistical powerD. Statistical significance - accurate answers-b. Type II
(beta)
The p-value is the probability that you would see that you saw in your sample,
or something even more extreme, assuming which of the following statements
is true?
A. When there is no difference between treatments
B. When the null hypothesis is true
C. When what you observed could have arisen solely by chance
D. All of the above - accurate answers-D. All of the above
Trivial effects may achieve statistical significance if the ______ is large enough.
A. Sample size
B. Z-score
C. P-value
D. Confidence interval - accurate answers-Sample size
If you fail to reject the null hypothesis, that is not proof of "no effect."
a. true
b. false - accurate answers-True
Which of the following p-values would be considered "statistically significant"
in most medical studies?
A. 0.058
B. 0.0058
C. 0.58D. None of the above would be considered statistically significant -
accurate answers-<0.05
0.0058
,A study with a large sample is broken down into many subgroups and each
individual in each subgroup is then analyzed before and after an exposure.
Testing the same data in many ways, such as in this example, may lead to
statistical significance about 1 in every 20 tests, though the significance may
be a change finding and entirely meaningless. This is an example of which type
of problem with p-values?
A. Error
B. Clinical vs statistical significance
C. Multiple testing
d. comparing p-values - accurate answers-C. Multiple testing
We are testing the effectiveness of a new vaccine. Our null hypothesis is that
the vaccine does not work to prevent the disease in question. If we conclude
that the vaccine works when in reality the null hypothesis is true, what type of
error have we made?
A. Type I (alpha)
B. Type II (beta)
C. Type III (statistical power)
D. We did not make an error - accurate answers-A. Type I (alpha)
T/F
You can prove the null hypothesis - accurate answers-False
Study designs often make comparisons within a group (ie. Did this group
compare itself at baseline?) and between multiple groups (ie, Did group A
improve more than group b?). For randomized, controlled trials ONLY effects
using this type of comparison are truly relevant and should be reported as the
primary outcome.
A. Within group effects
B. Between group effects
C. Both comparisons can be relevant D. Neither comparison are truly relevant
- accurate answers-Between-group effects
P-values depend on effect size, sample size, and variability. Which of the
following represents the correct relationship between these variables and
how then can affect p-values?
A. High effect size, low p-value
B. High sample size, low p-value
C. High variability, high p-value
, D. All of the above are correct - accurate answers-D. All of the above are
correct
Six women in study on lipid lowering agents are aged 52, 55, 56, 58, 59, and
92. What is the median? - accurate answers-57
The statistic that provides the average distance from the mean, and that is one
of the most important measures of variability is? - accurate answers-Standard
Deviation
When calculating a mean, we lose a degree of freedom. This becomes
important when we go to calculate: - accurate answers-standard deviation
Solve this factorial: 5!/2!3!: - accurate answers-10
Five women in a study on lipid lowering agents are aged 55,59, 52, 58, and 56.
Calculate the mean age: - accurate answers-56
The box plot represents what portion of data: - accurate answers-IQR: 50% of
ordered values
When thinking about a normal bell curve, what percentage of you data will fall
within 2 standard deviations of the mean? - accurate answers-95%
What is the equation of a line? - accurate answers-y=mx+b
Blood types is an example of what type of data? - accurate answers-
Categorical: nominal
Occasionally, it makes more sense to compare ____ when looking at skewed
data because it is unaffected by outliers unlike any other measurements -
accurate answers-Median
What's the correct way to interpret this risk ratio? Those who take low dose
aspirin regularly have 0.58 times the risk of myocardial infarction compared
to those who do not take aspirin. - accurate answers-Aspirin has a protective
effect (a decreased incidence) with lower risk of MI
