Multiple Choice

1. A Cox proportional hazards model is estimated relating time to psychiatric hospitalization in

patients with severe mental illness. The risk factors include age, sex, prior hospitalization for

mental illness, and an indicator of bipolar disorder. The

parameter estimates and significance levels for the model are shown here. Which of the predictors

are statistically significantly associated with time to psychiatric hospitalization?

PredictorParameter Estimatep-value Age, years

0.00450.5647

Sex (0 = female, 1 = male)-0.48410.0341

Prior hospitalization (0 = no, 1 = yes)0.37260.6178

Bipolar disorder (0 = no, 1 = yes)0.75610.0042

.

A) Sex & Bipolar disorder

B) Sex & Age

C) Prior hospitalization & Bipolar disorder

D) None of Above

2. The assumption that participant number 3 in the study below never developed the event of

interest would likely lead to which of the following statistical errors?

A) Noninf ormative censoring

B) Statistical censoring

C) Right censoring

D) Lef t censoring

3. The figure below shows survival probabilities from all-cause mortality over 20 years in

participants over 50 years of age who have normal glucose, glucose intolerance, and Type II

diabetes mellitus. Estimate the 5-year survival probability for Type II diabetes.

A) approximately 10%

B) approximately 60% C)approximately 76%

D) approximately 84%

4. Assume the below life table was constructed from following individuals who were diagnosed with a

slow-progressing form of prostate cancer and decided not to receive treatment of any form.

Calculate the survival probability at year 1 using the Kaplan-Meir approach and interpret the

results.

Time in YearsNumber at Risk, NtNumber of

t

Number Censored, Ct

Survival Probability

020

1

1203

2171

31621

A) The probability of surviving 1 year after being diagnosed with a slow-progressing form of

prostate cancer is .85.

B) The probability of surviving 1 year after being diagnosed with a slow-progressing form of

prostate cancer is .85 f or the individualsbeing followed in this study.

C) The probability of surviving 1 year after being diagnosed with a slow-progressing form of

prostate cancer is .85 f or individuals who decided against all forms of treatment.

D) The probability of surviving 1 year after being diagnosed with a slow-progressing form of

prostate cancer is .85 f or the individuals being followed in this study and for individuals who

decided against all forms of treatment.

5. Assume the below life table was constructed from following individuals who were diagnosed with a

slow-progressing form of prostate cancer and decided not to receive treatment of any form.

Calculate the survival probability at year 2 using the Kaplan-Meir approach and interpret the

results.

Time in YearsNumber at Risk, NtNumber of

t

Number Censored, Ct

Survival Probability

020

1

1203

217

1

31621

A) The probability of surviving 2 years after being diagnosed with a slow-progressing form of

prostate cancer is .85.

B) The probability of surviving 2 years after being diagnosed with a slow-progressing form of

prostate

cancer is .85 f or the individuals being followed in this study.

C) The probability of surviving 2 years after being diagnosed with a slow-progressing form of

prostate cancer is .85 f or individuals who decided against all forms oftreatment.

D) The probability of surviving 2 years after being diagnosed with a slow-progressing form of

prostate cancer is .85 f or the individuals being followed in this study and for individuals who

decided against all forms of treatment.

True/False

6. True or False? Assume the below life table was constructed from following individuals who were

diagnosed with slow-progressing form of prostate cancer and decided not to receive treatment of any

form. The calculated survival probability for year 3, if the Kaplan-Meir approach is used to

calculate the survival probability, is approximately 0.85.

Time in YearsNumber at Risk, NtNumber of

t

Number Censored, Ct

Survival Probability

020

1

1203

217

1

31621

7. True or False? Greenwood's formula allows one to calculate the standard error of the survival

estimates for a particular study.

8. True or False? According to the survival curve below, at 2 years of time the probability of

survival is approximately 90%.

9. True or False? According to the survival curve below, the probability of survival at 8 years of

time is approximately50%.

10. Trueor False? One of the most popular regression techniques for survival analysis is Cox

proportional hazards regression. Cox proportional hazards regression is used to relate several risk

factorsor exposures,consideredsimultaneously, to survival time.

Chapter 12

Multiple Choice

1. Which graphic representation could a researcher use to help determine if a continuous variable

followed a normaldistribution?

A) Bar chart

B) Pie chart

C) Box and Whisker Plot

D) Histogram and Box plot

2. Which graphic representation are appropriate when we wish to illustrate complex relationships

among variables that cannot be shown with tables or text, or to show trends or geographic

variations?

A) Bubble maps

B) Charts

C) Stem plots

D) Figures

3. A Column spanner in a table should describe which of the following?

A) The independent variable

B) The dependent variable

C) The covariate variable

D) The grouping variable

4. Which graph would be most useful in determining the change in two variables over time?

A) A line chart

B) A histogram

C) A bar chart

D) A f low chart

5. Which type of statistical information or graph would be most helpful in determining whether the

baseline characteristics of a study group are wellbalanced?

A) A bar chart

B) A box-whisker plot

C) Descriptive statistic

D) A f low chart

True/False

6. True or False? Using a 95% confidence interval to describe an odds ratio allows other

researchers to determine if the results were statistically significant because a statistically

significant odds ratio

conf idence interval will include the number 1.

7. True or False? The r2 value and a least squares regression line can be an excellent way to

demonstrate the degree of correlation between two variables, and the type of association between

the two variables.

8. True or False? Box-whisker plots are useful tools in comparing the median and the distribution

of two or more variables broken down into different categories.

9. True or False? Variable names and units of measurement should not be specified clearly and

accurately.

10. True or False? Good tables have clear and concise titles.