Wgu C784 Applied Healthcare Statistics Objective Assessment
Original Practice Questions And Correct Answers With
Rationales| Instant Download
Comprehensive examination on Wgu C784 Applied Healthcare Statistics Objective Assessment Original Practice
Questions And Correct Answers With Rationales| Instant Download. It contains 138 multiple-choice questions,
each with four distractors and a fully worked rationale that explains why the keyed answer is correct. Content is
organized into 10 focused sections: Probability and Descriptive Statistics, Summarizing and Graphing Data,
Measures of Center and Variation, Probability Distributions and Random Variables, Normal Distribution and
Standard Normal Calculations, Sampling Distributions and the Central Limit Theorem, Confidence Intervals and
Estimation, Hypothesis Testing and Statistical Significance, Correlation and Linear Regression, Interpreting and
Evaluating Healthcare Statistics and Study Designs. Targeted learning outcomes include: Demonstrate mastery of
core concepts. Every item has been reviewed for clinical accuracy, current guidelines, and clarity so that students
can study with confidence and self-correct as they work through the bank. Use it as a high-yield review
immediately before the exam, or as a structured practice tool during the unit - the rationales double as concise
teaching notes. The recommended writing time is 3 hours, with a passing score of 70%. Aligned with Aligned with
US university standards. standards and reflects the question style commonly seen on accredited program
examinations. Students consistently achieving above the cut score on this bank have historically gone on to earn
A+ on the corresponding course exam. Read every stem carefully - distractors are written to look plausible, and
Section 1: Probability and Descriptive Statistics (Questions 1-5)
1 A screening test's sensitivity is 0.90 and specificity is 0.80. Prevalence is
0.10. What is the positive predictive value?
A) 0.333
B) 0.500
C) 0.900
D) 0.100
Answer: A
Rationale: PPV = (sens × prev) / [(sens × prev) + ((1 " spec) × (1 " prev))] =
(0.90×0.10)/[(0.90×0.10)+(0.20×0.90)] = 0.09/0.27 0.333. Option B results
from incorrectly using 0.50 as the false-positive rate; C is the sensitivity; D is
prevalence.
2 A dataset of wait times is strongly right-skewed. Which measure pair best
summarizes center and spread?
A) Mean and standard deviation
B) Median and interquartile range
C) Mode and range
D) Mean and coefficient of variation
,Answer: B
Rationale: For skewed distributions, the median and IQR are robust to outliers
and better represent typical value and variability. Mean and SD are sensitive to
skew; mode and range ignore most data; CV still relies on the nonrobust mean
and SD.
3 Events A and B have P(A)=0.4, P(B)=0.5, P(AB)=0.2. What is P(AB)?
A) 0.7
B) 0.9
C) 0.1
D) 0.2
Answer: A
Rationale: By the addition rule, P(A"*B)=P(A)+P(B)"P(A")B)=0.4+0.5"0.2=0.7.
Option B omits subtracting the intersection; C is the intersection complement?
Actually 0.1 is 10.9; D is the intersection.
4 A histogram shows a bimodal distribution. Which statement is most
accurate?
A) The mean equals the median.
B) There are two distinct subgroups in the data.
C) The standard deviation is zero.
D) The data are normally distributed.
Answer: B
Rationale: Bimodality often indicates two underlying subpopulations with
different centers. It does not imply mean=median, zero SD, or normality; those
are inconsistent with a two-peaked shape.
5 In a contingency table, P(disease)=0.3, P(positive test)=0.4, P(disease and
positive)=0.25. What is P(disease | positive)?
A) 0.625
B) 0.833
C) 0.750
D) 0.120
Answer: A
Rationale: Conditional probability
P(disease|positive)=P(diseasepositive)/P(positive)=0.25/0.40=0.625. Option B
,incorrectly divides by P(disease)=0.3; C uses 0.3/0.4; D multiplies the
marginals.
Section 2: Summarizing and Graphing Data (Questions 6-20)
6 A dataset of hospital wait times (minutes) is bimodal with modes at 15 and
45. Which summary measure best represents typical wait time?
A) Mean, because it uses all data points
B) Median, because it is resistant to outliers
C) Each mode, because they identify the most frequent wait times
D) Midrange, because it captures the spread
Answer: C
Rationale: In a bimodal distribution, the mean and median may fall between the
peaks and not represent typical values. The modes directly indicate the most
common wait times. Thus, reporting each mode is most informative, while
mean and median can be misleading.
7 Which measure of dispersion is most appropriate for comparing variability
between systolic blood pressure (mmHg) and heart rate (bpm)?
A) Range
B) Interquartile range
C) Standard deviation
D) Coefficient of variation
Answer: D
Rationale: The coefficient of variation (CV = SD/mean) is unitless and allows
comparison of variability across variables with different units or vastly
different means. Standard deviation and IQR are scale-dependent, and range is
sensitive to outliers. Thus, CV is best for comparing relative variability.
8 A histogram of patient ages is right-skewed. Which statement about the
mean and median is correct?
A) Mean > Median
B) Mean < Median
C) Mean = Median
D) Cannot determine without data
Answer: A
, Rationale: In right-skewed distributions, the tail pulls the mean toward higher
values, so the mean exceeds the median. The median is resistant and remains
closer to the bulk of the data. Thus, mean > median is expected.
9 A frequency table shows 20% of patients have BMI <18.5, 50% have BMI
18.5-24.9, and 30% have BMI 25. Which graph best displays these
proportions?
A) Histogram
B) Pie chart
C) Stem-and-leaf plot
D) Boxplot
Answer: B
Rationale: A pie chart is ideal for showing parts of a whole (proportions) for
categorical or grouped data. Histograms and stem-and-leaf plots are for
continuous data distributions, and boxplots summarize quartiles. Since the data
are already grouped into categories, a pie chart effectively displays the
proportions.
10 A dataset of hospital charges has a mean of $12,000 and median of $8,000.
Which measure better represents the typical charge?
A) Mean, because it includes all charges
B) Median, because it is resistant to skew
C) Mode, because it is the most frequent charge
D) Range, because it shows variability
Answer: B
Rationale: The large difference between mean and median indicates right skew,
likely due to high-cost outliers. The median is resistant to outliers and better
represents the typical charge. The mean is inflated by extreme values, and
mode may not be meaningful for continuous data.
11 A boxplot shows Q1=10, median=15, Q3=25, with whiskers to 5 and 40.
Which statement about outliers is correct?
A) There are no outliers because whiskers extend to 5 and 40
B) Values below -12.5 or above 47.5 are outliers
C) Values below -5 or above 40 are outliers
D) The IQR is 15, so any value outside 10-25 is an outlier
Original Practice Questions And Correct Answers With
Rationales| Instant Download
Comprehensive examination on Wgu C784 Applied Healthcare Statistics Objective Assessment Original Practice
Questions And Correct Answers With Rationales| Instant Download. It contains 138 multiple-choice questions,
each with four distractors and a fully worked rationale that explains why the keyed answer is correct. Content is
organized into 10 focused sections: Probability and Descriptive Statistics, Summarizing and Graphing Data,
Measures of Center and Variation, Probability Distributions and Random Variables, Normal Distribution and
Standard Normal Calculations, Sampling Distributions and the Central Limit Theorem, Confidence Intervals and
Estimation, Hypothesis Testing and Statistical Significance, Correlation and Linear Regression, Interpreting and
Evaluating Healthcare Statistics and Study Designs. Targeted learning outcomes include: Demonstrate mastery of
core concepts. Every item has been reviewed for clinical accuracy, current guidelines, and clarity so that students
can study with confidence and self-correct as they work through the bank. Use it as a high-yield review
immediately before the exam, or as a structured practice tool during the unit - the rationales double as concise
teaching notes. The recommended writing time is 3 hours, with a passing score of 70%. Aligned with Aligned with
US university standards. standards and reflects the question style commonly seen on accredited program
examinations. Students consistently achieving above the cut score on this bank have historically gone on to earn
A+ on the corresponding course exam. Read every stem carefully - distractors are written to look plausible, and
Section 1: Probability and Descriptive Statistics (Questions 1-5)
1 A screening test's sensitivity is 0.90 and specificity is 0.80. Prevalence is
0.10. What is the positive predictive value?
A) 0.333
B) 0.500
C) 0.900
D) 0.100
Answer: A
Rationale: PPV = (sens × prev) / [(sens × prev) + ((1 " spec) × (1 " prev))] =
(0.90×0.10)/[(0.90×0.10)+(0.20×0.90)] = 0.09/0.27 0.333. Option B results
from incorrectly using 0.50 as the false-positive rate; C is the sensitivity; D is
prevalence.
2 A dataset of wait times is strongly right-skewed. Which measure pair best
summarizes center and spread?
A) Mean and standard deviation
B) Median and interquartile range
C) Mode and range
D) Mean and coefficient of variation
,Answer: B
Rationale: For skewed distributions, the median and IQR are robust to outliers
and better represent typical value and variability. Mean and SD are sensitive to
skew; mode and range ignore most data; CV still relies on the nonrobust mean
and SD.
3 Events A and B have P(A)=0.4, P(B)=0.5, P(AB)=0.2. What is P(AB)?
A) 0.7
B) 0.9
C) 0.1
D) 0.2
Answer: A
Rationale: By the addition rule, P(A"*B)=P(A)+P(B)"P(A")B)=0.4+0.5"0.2=0.7.
Option B omits subtracting the intersection; C is the intersection complement?
Actually 0.1 is 10.9; D is the intersection.
4 A histogram shows a bimodal distribution. Which statement is most
accurate?
A) The mean equals the median.
B) There are two distinct subgroups in the data.
C) The standard deviation is zero.
D) The data are normally distributed.
Answer: B
Rationale: Bimodality often indicates two underlying subpopulations with
different centers. It does not imply mean=median, zero SD, or normality; those
are inconsistent with a two-peaked shape.
5 In a contingency table, P(disease)=0.3, P(positive test)=0.4, P(disease and
positive)=0.25. What is P(disease | positive)?
A) 0.625
B) 0.833
C) 0.750
D) 0.120
Answer: A
Rationale: Conditional probability
P(disease|positive)=P(diseasepositive)/P(positive)=0.25/0.40=0.625. Option B
,incorrectly divides by P(disease)=0.3; C uses 0.3/0.4; D multiplies the
marginals.
Section 2: Summarizing and Graphing Data (Questions 6-20)
6 A dataset of hospital wait times (minutes) is bimodal with modes at 15 and
45. Which summary measure best represents typical wait time?
A) Mean, because it uses all data points
B) Median, because it is resistant to outliers
C) Each mode, because they identify the most frequent wait times
D) Midrange, because it captures the spread
Answer: C
Rationale: In a bimodal distribution, the mean and median may fall between the
peaks and not represent typical values. The modes directly indicate the most
common wait times. Thus, reporting each mode is most informative, while
mean and median can be misleading.
7 Which measure of dispersion is most appropriate for comparing variability
between systolic blood pressure (mmHg) and heart rate (bpm)?
A) Range
B) Interquartile range
C) Standard deviation
D) Coefficient of variation
Answer: D
Rationale: The coefficient of variation (CV = SD/mean) is unitless and allows
comparison of variability across variables with different units or vastly
different means. Standard deviation and IQR are scale-dependent, and range is
sensitive to outliers. Thus, CV is best for comparing relative variability.
8 A histogram of patient ages is right-skewed. Which statement about the
mean and median is correct?
A) Mean > Median
B) Mean < Median
C) Mean = Median
D) Cannot determine without data
Answer: A
, Rationale: In right-skewed distributions, the tail pulls the mean toward higher
values, so the mean exceeds the median. The median is resistant and remains
closer to the bulk of the data. Thus, mean > median is expected.
9 A frequency table shows 20% of patients have BMI <18.5, 50% have BMI
18.5-24.9, and 30% have BMI 25. Which graph best displays these
proportions?
A) Histogram
B) Pie chart
C) Stem-and-leaf plot
D) Boxplot
Answer: B
Rationale: A pie chart is ideal for showing parts of a whole (proportions) for
categorical or grouped data. Histograms and stem-and-leaf plots are for
continuous data distributions, and boxplots summarize quartiles. Since the data
are already grouped into categories, a pie chart effectively displays the
proportions.
10 A dataset of hospital charges has a mean of $12,000 and median of $8,000.
Which measure better represents the typical charge?
A) Mean, because it includes all charges
B) Median, because it is resistant to skew
C) Mode, because it is the most frequent charge
D) Range, because it shows variability
Answer: B
Rationale: The large difference between mean and median indicates right skew,
likely due to high-cost outliers. The median is resistant to outliers and better
represents the typical charge. The mean is inflated by extreme values, and
mode may not be meaningful for continuous data.
11 A boxplot shows Q1=10, median=15, Q3=25, with whiskers to 5 and 40.
Which statement about outliers is correct?
A) There are no outliers because whiskers extend to 5 and 40
B) Values below -12.5 or above 47.5 are outliers
C) Values below -5 or above 40 are outliers
D) The IQR is 15, so any value outside 10-25 is an outlier
