WGU C784 | Applied Healthcare Statistics - OA 1 2026/2027 | Verified Answers & A+ Solutions
WGU C784 Applied Healthcare Statistics
Objective Assessment 1 (OA 1) - 2026/2027
Comprehensive Exam with A+ Solutions and Verified Answers - Western Governors University
Total Questions: 90 (multiple choice, single best answer)
Cognitive Mix: 30% Recall | 50% Application | 20% Analysis
Format: 60% calculation/application | 40% conceptual/interpretation
Sections: 11 OA 1 competency domains (descriptive, probability, inferential)
Time Allotted: 120 minutes (average ~80 sec per question)
Passing Standard: WGU C784 OA 1 cut score - 70% correct (Competency-based)
Examination Instructions
1. Each question has four response options (A, B, C, D). Select the single best answer.
2. Calculation questions present data and require you to compute the answer. Rationales include step-by-step worked
solutions aligned with WGU C784 OA 1 competencies.
3. The Correct Answer and a Rationale are provided immediately beneath each question for self-study review.
4. Distractors represent common statistical errors and misconceptions (e.g., confusing Type I vs. Type II errors, reversing
sensitivity/specificity, misinterpreting confidence intervals, confusing correlation with causation).
5. The bolded teal accent line marks the correct option. All other options are plausible distractors reflecting typical student
statistical reasoning errors.
SECTION 1 | Introduction to Statistics, Data Types, and
Q1 - Q10
Levels of Measurement
Q1. A nurse researcher wants to summarize the ages of all patients admitted to a single hospital unit
during a calendar year using mean, median, and a histogram. Which branch of statistics does this activity
represent?
A. Inferential statistics, because the researcher is generalizing to a population
B. Descriptive statistics, because the researcher is summarizing and organizing data from a sample
or population without making inferences beyond the data set [CORRECT]
C. Predictive statistics, because future admissions are being forecast
D. Bayesian statistics, because prior probabilities are being updated
Correct Answer: B
Rationale: Descriptive statistics organize, summarize, and display data (mean, median, mode, range, variance, standard
deviation, graphs). Inferential statistics use sample data to draw conclusions about a larger population (hypothesis
testing, confidence intervals). Because the researcher is only summarizing the ages already collected (no inference
beyond the data set), this is descriptive statistics. OA 1 competency: distinguish descriptive vs. inferential statistics in
healthcare applications.
WGU C784 OA 1 - 90 Questions Page 1
,WGU C784 | Applied Healthcare Statistics - OA 1 2026/2027 | Verified Answers & A+ Solutions
Q2. A graduate nursing student classifies the following variables collected on ICU patients: heart rate
(beats per minute), blood type (A, B, AB, O), body temperature (Celsius), and satisfaction score (1=very
dissatisfied, 5=very satisfied). Which of the following correctly pairs a quantitative variable with its
subtype?
A. Blood type - quantitative discrete
B. Heart rate - quantitative continuous [CORRECT]
C. Satisfaction score - quantitative continuous
D. Body temperature - qualitative nominal
Correct Answer: B
Rationale: Heart rate (bpm) is quantitative (numeric) and continuous (can take any value within a range, including
fractional values such as 72.3 bpm measured by monitor). Blood type is qualitative (categorical) nominal. Satisfaction
score (1-5 Likert) is typically treated as ordinal qualitative (or sometimes interval quantitative) but is not continuous.
Body temperature in Celsius is quantitative continuous, NOT qualitative. OA 1 competency: variable types (quantitative
vs. qualitative; discrete vs. continuous).
Q3. Which of the following is a discrete quantitative variable in a healthcare setting?
A. Weight in kilograms
B. Blood pressure in mmHg
C. Number of falls per patient during hospitalization [CORRECT]
D. Length of stay in days and hours
Correct Answer: C
Rationale: A discrete variable can take only countable (typically whole-number) values. "Number of falls" can only be
0, 1, 2, 3, etc. - it is quantitative and discrete. Weight (A), blood pressure (B), and length of stay measured in days and
hours (D) can take fractional values and are continuous. Discrete quantitative variables often arise from counting
events (e.g., number of medications, number of pregnancies, number of prior surgeries).
Q4. A researcher records patient blood types as A, B, AB, or O. Which level of measurement does this
variable represent?
A. Nominal - categories with no inherent order [CORRECT]
B. Ordinal - categories with a meaningful order
C. Interval - ordered categories with equal intervals and no true zero
D. Ratio - ordered categories with equal intervals and a true zero
Correct Answer: A
Rationale: Blood type is at the nominal level: categories have names/labels (A, B, AB, O) but no inherent ranking or
order. You cannot say "AB is greater than A" in any meaningful numeric sense. Nominal data allow only counts and
modes (no median, mean, or ordered comparisons). The 4 levels in ascending order are nominal -> ordinal -> interval
-> ratio, with each adding more mathematical operations. OA 1 competency: levels of measurement (nominal, ordinal,
interval, ratio).
WGU C784 OA 1 - 90 Questions Page 2
,WGU C784 | Applied Healthcare Statistics - OA 1 2026/2027 | Verified Answers & A+ Solutions
Q5. A pain scale uses the categories: no pain, mild pain, moderate pain, severe pain, very severe pain.
Which level of measurement does this scale represent?
A. Nominal
B. Ordinal [CORRECT]
C. Interval
D. Ratio
Correct Answer: B
Rationale: The pain scale is ordinal: the categories have a meaningful order (no pain < mild < moderate < severe <
very severe) but the differences between adjacent categories are not necessarily equal (the "distance" from mild to
moderate may not equal that from moderate to severe), and there is no true zero point. Ordinal data allow median and
percentiles but not mean or standard deviation in strict terms. Likert scales in patient satisfaction surveys are also
ordinal. OA 1 competency: levels of measurement.
Q6. Body temperature measured in degrees Fahrenheit (F) is an example of which level of measurement?
A. Nominal
B. Ordinal
C. Interval [CORRECT]
D. Ratio
Correct Answer: C
Rationale: Temperature in Fahrenheit (or Celsius) is at the interval level: differences are meaningful and equal (the
change from 98F to 99F is the same amount of thermal energy as from 100F to 101F), but there is no true zero (0F
does not represent "no temperature" or absence of heat). Ratios are not meaningful (100F is not "twice as hot" as 50F).
Interval data support addition/subtraction and mean/standard deviation, but not ratios. OA 1: distinguish interval (no
true zero) from ratio (true zero).
Q7. A researcher records the length of hospital stay in days. This variable is measured at which level?
A. Nominal
B. Ordinal
C. Interval
D. Ratio [CORRECT]
Correct Answer: D
Rationale: Length of stay in days is at the ratio level: it has a true, non-arbitrary zero (0 days = no hospital stay), equal
intervals (the difference between 1 and 2 days equals the difference between 5 and 6 days), and ratios are meaningful
(a 6-day stay is genuinely twice as long as a 3-day stay). Other ratio-level examples include weight (kg), height (cm),
heart rate (bpm), blood pressure (mmHg), income, and time to event. OA 1: ratio data have a meaningful zero point; all
mathematical operations are valid.
WGU C784 OA 1 - 90 Questions Page 3
, WGU C784 | Applied Healthcare Statistics - OA 1 2026/2027 | Verified Answers & A+ Solutions
Q8. Which of the following healthcare variables is correctly classified at the nominal level?
A. Patient satisfaction (1-5 scale) - nominal
B. Birth weight in grams - nominal
C. Marital status (single, married, divorced, widowed) - nominal [CORRECT]
D. Apgar score (0-10) - nominal
Correct Answer: C
Rationale: Marital status is nominal because categories have names but no inherent order. Birth weight is ratio (true
zero, equal intervals, meaningful ratios). Satisfaction scales (1-5) and Apgar scores (0-10) are ordinal (or at best
interval if intervals are assumed equal) - they have order but no true zero and questionable equal intervals. OA 1 pitfall:
confusing ordinal and nominal. The presence of a meaningful order distinguishes ordinal from nominal.
Q9. A research study records the Glasgow Coma Scale (GCS) score for trauma patients on a scale from 3
(worst) to 15 (best). The level of measurement for the GCS is best described as:
A. Nominal
B. Ordinal [CORRECT]
C. Interval
D. Ratio
Correct Answer: B
Rationale: The GCS is ordinal: scores have a clear order (3 is worse than 15) but the differences between adjacent
scores are not necessarily equal in clinical severity (e.g., the difference between 3 and 4 is not the same as between 14
and 15). Although many studies report mean GCS for convenience, this is technically inappropriate - the median is more
correct. Likert-type scales in nursing research are similarly ordinal. OA 1: a scale with ordered categories but unequal
intervals is ordinal.
Q10. A researcher measures weight in pounds, height in inches, and BMI (kg/m2). All three variables are
at the ratio level. Which mathematical operation is appropriate for ratio-level data that is NOT
appropriate for nominal or ordinal data?
A. Counting frequencies in each category
B. Sorting observations into ordered categories
C. Computing meaningful ratios (e.g., patient A weighs twice as much as patient B) [CORRECT]
D. Reporting the mode
Correct Answer: C
Rationale: Ratio-level data uniquely allow meaningful ratios because the zero point is true and non-arbitrary. For
example, a 200-lb patient weighs twice as much as a 100-lb patient, and a heart rate of 120 is twice that of 60. Nominal
data (A, D) only allow counting; ordinal data (B) allow ordering. Computing ratios on nominal or ordinal data is
meaningless. OA 1 competency: the 4 levels form a hierarchy (nominal -> ordinal -> interval -> ratio), and each higher
level adds a meaningful mathematical operation.
SECTION 2 | Data Collection, Sampling Methods, Bias, and
Q11 - Q20
Study Design
WGU C784 OA 1 - 90 Questions Page 4
WGU C784 Applied Healthcare Statistics
Objective Assessment 1 (OA 1) - 2026/2027
Comprehensive Exam with A+ Solutions and Verified Answers - Western Governors University
Total Questions: 90 (multiple choice, single best answer)
Cognitive Mix: 30% Recall | 50% Application | 20% Analysis
Format: 60% calculation/application | 40% conceptual/interpretation
Sections: 11 OA 1 competency domains (descriptive, probability, inferential)
Time Allotted: 120 minutes (average ~80 sec per question)
Passing Standard: WGU C784 OA 1 cut score - 70% correct (Competency-based)
Examination Instructions
1. Each question has four response options (A, B, C, D). Select the single best answer.
2. Calculation questions present data and require you to compute the answer. Rationales include step-by-step worked
solutions aligned with WGU C784 OA 1 competencies.
3. The Correct Answer and a Rationale are provided immediately beneath each question for self-study review.
4. Distractors represent common statistical errors and misconceptions (e.g., confusing Type I vs. Type II errors, reversing
sensitivity/specificity, misinterpreting confidence intervals, confusing correlation with causation).
5. The bolded teal accent line marks the correct option. All other options are plausible distractors reflecting typical student
statistical reasoning errors.
SECTION 1 | Introduction to Statistics, Data Types, and
Q1 - Q10
Levels of Measurement
Q1. A nurse researcher wants to summarize the ages of all patients admitted to a single hospital unit
during a calendar year using mean, median, and a histogram. Which branch of statistics does this activity
represent?
A. Inferential statistics, because the researcher is generalizing to a population
B. Descriptive statistics, because the researcher is summarizing and organizing data from a sample
or population without making inferences beyond the data set [CORRECT]
C. Predictive statistics, because future admissions are being forecast
D. Bayesian statistics, because prior probabilities are being updated
Correct Answer: B
Rationale: Descriptive statistics organize, summarize, and display data (mean, median, mode, range, variance, standard
deviation, graphs). Inferential statistics use sample data to draw conclusions about a larger population (hypothesis
testing, confidence intervals). Because the researcher is only summarizing the ages already collected (no inference
beyond the data set), this is descriptive statistics. OA 1 competency: distinguish descriptive vs. inferential statistics in
healthcare applications.
WGU C784 OA 1 - 90 Questions Page 1
,WGU C784 | Applied Healthcare Statistics - OA 1 2026/2027 | Verified Answers & A+ Solutions
Q2. A graduate nursing student classifies the following variables collected on ICU patients: heart rate
(beats per minute), blood type (A, B, AB, O), body temperature (Celsius), and satisfaction score (1=very
dissatisfied, 5=very satisfied). Which of the following correctly pairs a quantitative variable with its
subtype?
A. Blood type - quantitative discrete
B. Heart rate - quantitative continuous [CORRECT]
C. Satisfaction score - quantitative continuous
D. Body temperature - qualitative nominal
Correct Answer: B
Rationale: Heart rate (bpm) is quantitative (numeric) and continuous (can take any value within a range, including
fractional values such as 72.3 bpm measured by monitor). Blood type is qualitative (categorical) nominal. Satisfaction
score (1-5 Likert) is typically treated as ordinal qualitative (or sometimes interval quantitative) but is not continuous.
Body temperature in Celsius is quantitative continuous, NOT qualitative. OA 1 competency: variable types (quantitative
vs. qualitative; discrete vs. continuous).
Q3. Which of the following is a discrete quantitative variable in a healthcare setting?
A. Weight in kilograms
B. Blood pressure in mmHg
C. Number of falls per patient during hospitalization [CORRECT]
D. Length of stay in days and hours
Correct Answer: C
Rationale: A discrete variable can take only countable (typically whole-number) values. "Number of falls" can only be
0, 1, 2, 3, etc. - it is quantitative and discrete. Weight (A), blood pressure (B), and length of stay measured in days and
hours (D) can take fractional values and are continuous. Discrete quantitative variables often arise from counting
events (e.g., number of medications, number of pregnancies, number of prior surgeries).
Q4. A researcher records patient blood types as A, B, AB, or O. Which level of measurement does this
variable represent?
A. Nominal - categories with no inherent order [CORRECT]
B. Ordinal - categories with a meaningful order
C. Interval - ordered categories with equal intervals and no true zero
D. Ratio - ordered categories with equal intervals and a true zero
Correct Answer: A
Rationale: Blood type is at the nominal level: categories have names/labels (A, B, AB, O) but no inherent ranking or
order. You cannot say "AB is greater than A" in any meaningful numeric sense. Nominal data allow only counts and
modes (no median, mean, or ordered comparisons). The 4 levels in ascending order are nominal -> ordinal -> interval
-> ratio, with each adding more mathematical operations. OA 1 competency: levels of measurement (nominal, ordinal,
interval, ratio).
WGU C784 OA 1 - 90 Questions Page 2
,WGU C784 | Applied Healthcare Statistics - OA 1 2026/2027 | Verified Answers & A+ Solutions
Q5. A pain scale uses the categories: no pain, mild pain, moderate pain, severe pain, very severe pain.
Which level of measurement does this scale represent?
A. Nominal
B. Ordinal [CORRECT]
C. Interval
D. Ratio
Correct Answer: B
Rationale: The pain scale is ordinal: the categories have a meaningful order (no pain < mild < moderate < severe <
very severe) but the differences between adjacent categories are not necessarily equal (the "distance" from mild to
moderate may not equal that from moderate to severe), and there is no true zero point. Ordinal data allow median and
percentiles but not mean or standard deviation in strict terms. Likert scales in patient satisfaction surveys are also
ordinal. OA 1 competency: levels of measurement.
Q6. Body temperature measured in degrees Fahrenheit (F) is an example of which level of measurement?
A. Nominal
B. Ordinal
C. Interval [CORRECT]
D. Ratio
Correct Answer: C
Rationale: Temperature in Fahrenheit (or Celsius) is at the interval level: differences are meaningful and equal (the
change from 98F to 99F is the same amount of thermal energy as from 100F to 101F), but there is no true zero (0F
does not represent "no temperature" or absence of heat). Ratios are not meaningful (100F is not "twice as hot" as 50F).
Interval data support addition/subtraction and mean/standard deviation, but not ratios. OA 1: distinguish interval (no
true zero) from ratio (true zero).
Q7. A researcher records the length of hospital stay in days. This variable is measured at which level?
A. Nominal
B. Ordinal
C. Interval
D. Ratio [CORRECT]
Correct Answer: D
Rationale: Length of stay in days is at the ratio level: it has a true, non-arbitrary zero (0 days = no hospital stay), equal
intervals (the difference between 1 and 2 days equals the difference between 5 and 6 days), and ratios are meaningful
(a 6-day stay is genuinely twice as long as a 3-day stay). Other ratio-level examples include weight (kg), height (cm),
heart rate (bpm), blood pressure (mmHg), income, and time to event. OA 1: ratio data have a meaningful zero point; all
mathematical operations are valid.
WGU C784 OA 1 - 90 Questions Page 3
, WGU C784 | Applied Healthcare Statistics - OA 1 2026/2027 | Verified Answers & A+ Solutions
Q8. Which of the following healthcare variables is correctly classified at the nominal level?
A. Patient satisfaction (1-5 scale) - nominal
B. Birth weight in grams - nominal
C. Marital status (single, married, divorced, widowed) - nominal [CORRECT]
D. Apgar score (0-10) - nominal
Correct Answer: C
Rationale: Marital status is nominal because categories have names but no inherent order. Birth weight is ratio (true
zero, equal intervals, meaningful ratios). Satisfaction scales (1-5) and Apgar scores (0-10) are ordinal (or at best
interval if intervals are assumed equal) - they have order but no true zero and questionable equal intervals. OA 1 pitfall:
confusing ordinal and nominal. The presence of a meaningful order distinguishes ordinal from nominal.
Q9. A research study records the Glasgow Coma Scale (GCS) score for trauma patients on a scale from 3
(worst) to 15 (best). The level of measurement for the GCS is best described as:
A. Nominal
B. Ordinal [CORRECT]
C. Interval
D. Ratio
Correct Answer: B
Rationale: The GCS is ordinal: scores have a clear order (3 is worse than 15) but the differences between adjacent
scores are not necessarily equal in clinical severity (e.g., the difference between 3 and 4 is not the same as between 14
and 15). Although many studies report mean GCS for convenience, this is technically inappropriate - the median is more
correct. Likert-type scales in nursing research are similarly ordinal. OA 1: a scale with ordered categories but unequal
intervals is ordinal.
Q10. A researcher measures weight in pounds, height in inches, and BMI (kg/m2). All three variables are
at the ratio level. Which mathematical operation is appropriate for ratio-level data that is NOT
appropriate for nominal or ordinal data?
A. Counting frequencies in each category
B. Sorting observations into ordered categories
C. Computing meaningful ratios (e.g., patient A weighs twice as much as patient B) [CORRECT]
D. Reporting the mode
Correct Answer: C
Rationale: Ratio-level data uniquely allow meaningful ratios because the zero point is true and non-arbitrary. For
example, a 200-lb patient weighs twice as much as a 100-lb patient, and a heart rate of 120 is twice that of 60. Nominal
data (A, D) only allow counting; ordinal data (B) allow ordering. Computing ratios on nominal or ordinal data is
meaningless. OA 1 competency: the 4 levels form a hierarchy (nominal -> ordinal -> interval -> ratio), and each higher
level adds a meaningful mathematical operation.
SECTION 2 | Data Collection, Sampling Methods, Bias, and
Q11 - Q20
Study Design
WGU C784 OA 1 - 90 Questions Page 4
