Complete Solution Manual Fundamentals of
Biostatistics 8th Edition Rosner Questions & Answers
with rationales
# Section 1: Descriptive Statistics & Data Visualization
Question 1
In a study examining cholesterol levels, data on 100 patients shows a distribution
that is positively skewed. Which measure of central tendency would best represent
the "typical" cholesterol level in this group?
A) The mean, because it uses all data points
B) The mode, because it is the most frequent value
C) The median, because it is resistant to the influence of extreme values
D) The range, because it shows the spread of the data
Correct Answer: C
Rationale: For a positively skewed distribution, the mean is pulled towards the
long tail by high outlier values, making it a poor representation of the central or
"typical" value. The median is considered a "resistant" measure because it is not
heavily influenced by extreme scores and provides a better location estimate of the
center for skewed data .
Question 2
1
, A researcher is investigating the relationship between age and systolic blood
pressure. According to the empirical rule, approximately what percentage of the
data in a normally distributed population of systolic blood pressure values falls
within 2 standard deviations of the mean?
A) 50%
B) 68%
C) 95%
D) 99.7%
Correct Answer: C
Rationale: The Empirical Rule states that for a normal distribution: 68% of the data
falls within ±1 standard deviation of the mean, 95% within ±2 standard deviations,
and 99.7% within ±3 standard deviations . This is a foundational concept in
biostatistics for understanding the spread of data and identifying outliers.
# Section 2: Study Design & Epidemiology
Question 3
You are designing a study to investigate a rare disease. You plan to identify a group
of individuals who already have the disease and a control group of healthy
individuals, and then look back at their medical records to find potential risk
factors. This type of study is best described as:
A) A prospective cohort study
B) A retrospective case-control study
C) A randomized controlled trial
D) A cross-sectional study
2
Biostatistics 8th Edition Rosner Questions & Answers
with rationales
# Section 1: Descriptive Statistics & Data Visualization
Question 1
In a study examining cholesterol levels, data on 100 patients shows a distribution
that is positively skewed. Which measure of central tendency would best represent
the "typical" cholesterol level in this group?
A) The mean, because it uses all data points
B) The mode, because it is the most frequent value
C) The median, because it is resistant to the influence of extreme values
D) The range, because it shows the spread of the data
Correct Answer: C
Rationale: For a positively skewed distribution, the mean is pulled towards the
long tail by high outlier values, making it a poor representation of the central or
"typical" value. The median is considered a "resistant" measure because it is not
heavily influenced by extreme scores and provides a better location estimate of the
center for skewed data .
Question 2
1
, A researcher is investigating the relationship between age and systolic blood
pressure. According to the empirical rule, approximately what percentage of the
data in a normally distributed population of systolic blood pressure values falls
within 2 standard deviations of the mean?
A) 50%
B) 68%
C) 95%
D) 99.7%
Correct Answer: C
Rationale: The Empirical Rule states that for a normal distribution: 68% of the data
falls within ±1 standard deviation of the mean, 95% within ±2 standard deviations,
and 99.7% within ±3 standard deviations . This is a foundational concept in
biostatistics for understanding the spread of data and identifying outliers.
# Section 2: Study Design & Epidemiology
Question 3
You are designing a study to investigate a rare disease. You plan to identify a group
of individuals who already have the disease and a control group of healthy
individuals, and then look back at their medical records to find potential risk
factors. This type of study is best described as:
A) A prospective cohort study
B) A retrospective case-control study
C) A randomized controlled trial
D) A cross-sectional study
2
