Question 1

The median survival time cannot be calculated for studies in which the survival proportion fails to reach 0.050.

Accepted Answer

A) True 
 B)False  True

Question 2

Consider the data table showing patients in a trial in which 30 are given a placebo and 20 are given an experimental drug and the deaths are recorded over a period of 24 months.
​
 $\begin{array}{c}
\underline {  \text {  Control}   }  \quad \quad \quad \quad \quad \quad \quad \quad\underline { \text { Exp. drug}}\
\begin{array}{cccc}
\text { Time } & \text { \# at risk } & \text { Deaths } & \text { \# at risk } & \text { Deaths } \
3 & 30 & 5 & 20 & 1 \
6 & 25 & 6 & 18 & 2 \
9 & 19 & 3 & 16 & 1 \
12 & 16 & 3 & 15 & 2 \
24 & 13 & 2 & 13 & 1
\end{array}\end{array}$
-What is the 95% confidence interval of the hazard ratio for the control group relative to the drug treatment group?

Accepted Answer

A)  From 0.905 to 5.118 
B)  From 0.992 to 4.665 
C)  From 1.439 to 8.145 
D)  From 1.579 to 7.425 
A)  From 0.905 to 5.118 
B)  From 0.992 to 4.665 
C)  From 1.439 to 8.145 
D)  From 1.579 to 7.425 B

Question 3

Consider the data table showing patients in a trial in which 30 are given a placebo and 20 are given an experimental drug and the deaths are recorded over a period of 24 months.
​
 $\begin{array}{c}
\underline {  \text {  Control}   }  \quad \quad \quad \quad \quad \quad \quad \quad\underline { \text { Exp. drug}}\
\begin{array}{cccc}
\text { Time } & \text { \# at risk } & \text { Deaths } & \text { \# at risk } & \text { Deaths } \
3 & 30 & 5 & 20 & 1 \
6 & 25 & 6 & 18 & 2 \
9 & 19 & 3 & 16 & 1 \
12 & 16 & 3 & 15 & 2 \
24 & 13 & 2 & 13 & 1
\end{array}\end{array}$
-What is the hazard ratio for the control group relative to the drug treatment group?

Accepted Answer

A)  2.152 
B)  2.768 
C)  3.424 
D)  3.783 
A)  2.152 
B)  2.768 
C)  3.424 
D)  3.783 A

Question 4

Consider the data table showing epidemiology data for 25 individuals with a disease and 25 healthy comparison individuals. Their deaths are recorded over a period of 12 months.
​
 $\begin{array}{c}
\underline {  \text {  Diseased }   }  \quad \quad \quad \quad \quad \quad \quad \quad\underline { \text { Healthy}}\
\begin{array}{cccc}
\text { Time } & \text { \# at risk } & \text { Deaths } & \text { \# at risk } & \text { Deaths } \
2 & 25 & 1 & 25 & 2 \
4 & 24 & 3 & 23 & 5 \
6 & 21 & 1 & 18 & 4 \
8 & 20 & 2 & 13 & 3 \
10 & 18 & 0 & 10 & 1 \
12 & 18 & 1 & 9 & 2
\end{array}\end{array}$
-What is the 95% confidence interval of the hazard ratio for the disease group relative to the healthy group?

Accepted Answer

A)  From 0.169 to 0.821 
B)  From 0.212 to 1.110 
C)  From 0.256 to 1.377 
D)  From 0.270 to 1.308 
A)  From 0.169 to 0.821 
B)  From 0.212 to 1.110 
C)  From 0.256 to 1.377 
D)  From 0.270 to 1.308

Question 5

Explain conceptually why we can use censored data in survival analyses, but we are unable to use censored data in other techniques.

Accepted Answer

Survival analysis is a statistical techn

Question 6

Consider the data table showing patients in a trial in which 30 are given a placebo and 20 are given an experimental drug and the deaths are recorded over a period of 24 months.
​
 $\begin{array}{c}
\underline {  \text {  Control}   }  \quad \quad \quad \quad \quad \quad \quad \quad\underline { \text { Exp. drug}}\
\begin{array}{cccc}
\text { Time } & \text { \# at risk } & \text { Deaths } & \text { \# at risk } & \text { Deaths } \
3 & 30 & 5 & 20 & 1 \
6 & 25 & 6 & 18 & 2 \
9 & 19 & 3 & 16 & 1 \
12 & 16 & 3 & 15 & 2 \
24 & 13 & 2 & 13 & 1
\end{array}\end{array}$
-Based on the ?2 value from a test of the hazard ratio for the control group relative to the drug treatment group, what is our conclusion?

Accepted Answer

A)  P  0.05, the survival curves are the same. 
D)  P > 0.05, the survival curves differ from each other. 
A)  P  0.05, the survival curves are the same. 
D)  P > 0.05, the survival curves differ from each other.

Question 7

The assumption of proportional hazards when using the Kaplan-Meier method states which of the following?

Accepted Answer

A)  The hazard ratio between the two groups must be normally distributed. 
B)  The hazard ratio between the two groups stays constant over time. 
C)  The hazard ratio is in direct proportion to the sample sizes in each group. 
D)  The hazard ratio is the same as the overall number of deaths in each group. 
A)  The hazard ratio between the two groups must be normally distributed. 
B)  The hazard ratio between the two groups stays constant over time. 
C)  The hazard ratio is in direct proportion to the sample sizes in each group. 
D)  The hazard ratio is the same as the overall number of deaths in each group.

Question 8

A key assumption of the Kaplan-Meier method for calculating survival curves is which of the following?

Accepted Answer

A)  All individuals eventually experience the event of interest. 
B)  All subjects, including censored ones, have the same probabilities of experiencing events in each time period. 
C)  Fewer than 5% of individuals are censored. 
D)  Probabilities of experiencing events are constant across all time periods. 
A)  All individuals eventually experience the event of interest. 
B)  All subjects, including censored ones, have the same probabilities of experiencing events in each time period. 
C)  Fewer than 5% of individuals are censored. 
D)  Probabilities of experiencing events are constant across all time periods.

Question 9

Consider the data table showing epidemiology data for 25 individuals with a disease and 25 healthy comparison individuals. Their deaths are recorded over a period of 12 months.
​
 $\begin{array}{c}
\underline {  \text {  Diseased }   }  \quad \quad \quad \quad \quad \quad \quad \quad\underline { \text { Healthy}}\
\begin{array}{cccc}
\text { Time } & \text { \# at risk } & \text { Deaths } & \text { \# at risk } & \text { Deaths } \
2 & 25 & 1 & 25 & 2 \
4 & 24 & 3 & 23 & 5 \
6 & 21 & 1 & 18 & 4 \
8 & 20 & 2 & 13 & 3 \
10 & 18 & 0 & 10 & 1 \
12 & 18 & 1 & 9 & 2
\end{array}\end{array}$
-What is the ?2 value we obtain from a ?2 test of the hazard ratio for the disease group relative to the healthy group?

Accepted Answer

A)  3.850 
B)  5.526 
C)  5.743 
D)  7.134 
A)  3.850 
B)  5.526 
C)  5.743 
D)  7.134

Question 10

Consider the data table showing epidemiology data for 25 individuals with a disease and 25 healthy comparison individuals. Their deaths are recorded over a period of 12 months.
​
 $\begin{array}{c}
\underline {  \text {  Diseased }   }  \quad \quad \quad \quad \quad \quad \quad \quad\underline { \text { Healthy}}\
\begin{array}{cccc}
\text { Time } & \text { \# at risk } & \text { Deaths } & \text { \# at risk } & \text { Deaths } \
2 & 25 & 1 & 25 & 2 \
4 & 24 & 3 & 23 & 5 \
6 & 21 & 1 & 18 & 4 \
8 & 20 & 2 & 13 & 3 \
10 & 18 & 0 & 10 & 1 \
12 & 18 & 1 & 9 & 2
\end{array}\end{array}$
-What is the standard error of the natural log of the hazard ratio for the disease group relative to the healthy group?

Accepted Answer

A)  0.200 
B)  0.302 
C)  0.403 
D)  0.429 
A)  0.200 
B)  0.302 
C)  0.403 
D)  0.429

Question 11

The Kaplan-Meier method assumes the probabilities of survival for censored subjects are the same as those who remain in the study.

Accepted Answer

A) True 
 B)False

Question 12

If D1 and D2 are the observed deaths in the two groups while E1 and E2 are the expected number of deaths for the two groups, which of the following is the correct equation for the hazard ratio?

Accepted Answer

A)  HR = ( D1/D2 ) / ( E1/E2 ) 
B)  HR = ( D1/D2 ) / ( E2/E1 ) 
C)  HR = ( D2/D1 ) / ( E1/E2 ) 
D)  HR = ( D2/D1 ) / ( E2/E1 ) 
A)  HR = ( D1/D2 ) / ( E1/E2 ) 
B)  HR = ( D1/D2 ) / ( E2/E1 ) 
C)  HR = ( D2/D1 ) / ( E1/E2 ) 
D)  HR = ( D2/D1 ) / ( E2/E1 )

Question 13

Consider the data table showing patients in a trial in which 30 are given a placebo and 20 are given an experimental drug and the deaths are recorded over a period of 24 months.
​
 $\begin{array}{c}
\underline {  \text {  Control}   }  \quad \quad \quad \quad \quad \quad \quad \quad\underline { \text { Exp. drug}}\
\begin{array}{cccc}
\text { Time } & \text { \# at risk } & \text { Deaths } & \text { \# at risk } & \text { Deaths } \
3 & 30 & 5 & 20 & 1 \
6 & 25 & 6 & 18 & 2 \
9 & 19 & 3 & 16 & 1 \
12 & 16 & 3 & 15 & 2 \
24 & 13 & 2 & 13 & 1
\end{array}\end{array}$
-What is the standard error of the natural log of the hazard ratio for the control group relative to the drug treatment group?

Accepted Answer

A)  0.196 
B)  0.395 
C)  0.442 
D)  0.503 
A)  0.196 
B)  0.395 
C)  0.442 
D)  0.503

Question 14

The 95% confidence intervals in a survival curve become wider for later time periods because there are fewer individual remaining and the estimate is therefore less precise.

Accepted Answer

A) True 
 B)False

Question 15

The value that measures the hazard rate in a group, relative to that in the other group at a particular time, is called which of the following?

Accepted Answer

A)  The hazard fraction 
B)  The hazard ratio 
C)  The hazard proportion 
D)  The hazard value 
A)  The hazard fraction 
B)  The hazard ratio 
C)  The hazard proportion 
D)  The hazard value

Question 16

Describe a real-world situation in which a survival analysis would not be feasible because the proportional hazards assumption is violated.

Accepted Answer

One real-world situation in which surviv

Question 17

Consider the data table showing epidemiology data for 36 individuals with a disease and 38 healthy comparison individuals. Their deaths are recorded over a period of 16 months.
​
 $\begin{array}{c}
\underline {  \text {  Diseased }   }  \quad \quad \quad \quad \quad \quad \quad \quad\underline { \text { Healthy}}\
\begin{array}{cccc}
\text { Time } & \text { \# at risk } & \text { Deaths } & \text { \# at risk } & \text { Deaths } \
2 & 36 & 2 & 38 & 2 \
4 & 33 & 7 & 35 & 4 \
6 & 25 & 5 & 31 & 3 \
8 & 20 & 5 & 27 & 4 \
10 & 15 & 2 & 20 & 2 \
12 & 13 & 3 & 18 & 3 \
14 & 9 & 1 & 14 & 1 \
16 & 8 & 1 & 12 & 2
\end{array}\end{array}$ 
a.Calculate the hazard ratio and 95% confidence interval for the hazard ratio.
b.Perform a χ2 test on the hazard ratio. Present the χ2 value, a range for the P-value it corresponds to, and the interpretation of your test.

Accepted Answer

a. To calculate the hazard ratio, we can

Question 18

Survival curves displays what value on the Y-axis?

Accepted Answer

A)  The probability of an individual experiencing an event in that time period 
B)  The probability of an individual surviving to the next time period 
C)  The proportion of individuals remaining from the initial sample 
D)  The proportion of individuals that have not experienced an event 
A)  The probability of an individual experiencing an event in that time period 
B)  The probability of an individual surviving to the next time period 
C)  The proportion of individuals remaining from the initial sample 
D)  The proportion of individuals that have not experienced an event

Question 19

Consider the data table showing epidemiology data for 25 individuals with a disease and 25 healthy comparison individuals. Their deaths are recorded over a period of 12 months.
​
 $\begin{array}{c}
\underline {  \text {  Diseased }   }  \quad \quad \quad \quad \quad \quad \quad \quad\underline { \text { Healthy}}\
\begin{array}{cccc}
\text { Time } & \text { \# at risk } & \text { Deaths } & \text { \# at risk } & \text { Deaths } \
2 & 25 & 1 & 25 & 2 \
4 & 24 & 3 & 23 & 5 \
6 & 21 & 1 & 18 & 4 \
8 & 20 & 2 & 13 & 3 \
10 & 18 & 0 & 10 & 1 \
12 & 18 & 1 & 9 & 2
\end{array}\end{array}$
-What is the hazard ratio for the disease group relative to the healthy group?

Accepted Answer

A)  0.373. 
B)  0.594. 
C)  1.683. 
D)  2.683. 
A)  0.373. 
B)  0.594. 
C)  1.683. 
D)  2.683.

Question 20

Consider the data table showing epidemiology data for 25 individuals with a disease and 25 healthy comparison individuals. Their deaths are recorded over a period of 12 months.
​
 $\begin{array}{c}
\underline {  \text {  Diseased }   }  \quad \quad \quad \quad \quad \quad \quad \quad\underline { \text { Healthy}}\
\begin{array}{cccc}
\text { Time } & \text { \# at risk } & \text { Deaths } & \text { \# at risk } & \text { Deaths } \
2 & 25 & 1 & 25 & 2 \
4 & 24 & 3 & 23 & 5 \
6 & 21 & 1 & 18 & 4 \
8 & 20 & 2 & 13 & 3 \
10 & 18 & 0 & 10 & 1 \
12 & 18 & 1 & 9 & 2
\end{array}\end{array}$
-Based on the ?2 value from a test of the hazard ratio for the disease group relative to the healthy group, what is our conclusion?

Accepted Answer

A)  P  0.05, the survival curves are the same. 
D)  P > 0.05, the survival curves differ from each other. 
A)  P  0.05, the survival curves are the same. 
D)  P > 0.05, the survival curves differ from each other.

The median survival time cannot be calculated for studies in which the survival proportion fails to reach 0.050.

Explain conceptually why we can use censored data in survival analyses, but we are unable to use censored data in other techniques.

The assumption of proportional hazards when using the Kaplan-Meier method states which of the following?

A key assumption of the Kaplan-Meier method for calculating survival curves is which of the following?

The Kaplan-Meier method assumes the probabilities of survival for censored subjects are the same as those who remain in the study.

If D₁ and D₂ are the observed deaths in the two groups while E₁ and E₂ are the expected number of deaths for the two groups, which of the following is the correct equation for the hazard ratio?

The 95% confidence intervals in a survival curve become wider for later time periods because there are fewer individual remaining and the estimate is therefore less precise.

The value that measures the hazard rate in a group, relative to that in the other group at a particular time, is called which of the following?

Describe a real-world situation in which a survival analysis would not be feasible because the proportional hazards assumption is violated.

Survival curves displays what value on the Y-axis?

Statistics and Samples

Displaying Data

Describing Data

Estimating With Uncertainty

Probability

Hypothesis Testing

Analyzing Proportions

Fitting Probability Models to Frequency Data

Contingency Analysis: Associations Between

The Normal Distribution

Inference for a Normal Population

Comparing Two Means

Handling Violations of Assumptions

Designing Experiments

Comparing Means of More Than Two Groups

Correlation Between Numerical Variables

Regression

Multiple Explanatory Variables

Computer-Intensive Methods

Likelihood

Filters

Exam 21: Meta-Analysis: Combining Information From

The median survival time cannot be calculated for studies in which the survival proportion fails to reach 0.050.

Explain conceptually why we can use censored data in survival analyses, but we are unable to use censored data in other techniques.

The assumption of proportional hazards when using the Kaplan-Meier method states which of the following?

A key assumption of the Kaplan-Meier method for calculating survival curves is which of the following?

The Kaplan-Meier method assumes the probabilities of survival for censored subjects are the same as those who remain in the study.

If D1 and D2 are the observed deaths in the two groups while E1 and E2 are the expected number of deaths for the two groups, which of the following is the correct equation for the hazard ratio?

The 95% confidence intervals in a survival curve become wider for later time periods because there are fewer individual remaining and the estimate is therefore less precise.

The value that measures the hazard rate in a group, relative to that in the other group at a particular time, is called which of the following?

Describe a real-world situation in which a survival analysis would not be feasible because the proportional hazards assumption is violated.

Survival curves displays what value on the Y-axis?

Statistics and Samples

Displaying Data

Describing Data

Estimating With Uncertainty

Probability

Hypothesis Testing

Analyzing Proportions

Fitting Probability Models to Frequency Data

Contingency Analysis: Associations Between

The Normal Distribution

Inference for a Normal Population

Comparing Two Means

Handling Violations of Assumptions

Designing Experiments

Comparing Means of More Than Two Groups

Correlation Between Numerical Variables

Regression

Multiple Explanatory Variables

Computer-Intensive Methods

Likelihood

Filters

If D₁ and D₂ are the observed deaths in the two groups while E₁ and E₂ are the expected number of deaths for the two groups, which of the following is the correct equation for the hazard ratio?