C785 Applied Healthcare Statistics - Week 6 Quiz 2026 WGU
1. What is the sum of the probabilities of all possible outcomes in a sample
space?
A. 1.0
B. 0.5
C. 0.0
D. 100
Answer: A
Rationale: In any probability distribution, the sum of all possible outcomes must equal 1.0
(or 100%).
2. Which of the following describes two events that cannot occur at the same
time?
A. Mutually exclusive events
B. Dependent events
C. Independent events
D. Conditional events
Answer: A
Rationale: Mutually exclusive events (or disjoint events) are events that cannot happen
simultaneously.
,3. In a standard normal distribution, what is the mean?
A. 1
B. 0.5
C. 10
D. 0
Answer: D
Rationale: The standard normal distribution (Z-distribution) always has a mean of 0 and a
standard deviation of 1.
4. In a standard normal distribution, what is the standard deviation?
A. 0
B. 1
C. 0.5
D. Variable
Answer: B
Rationale: By definition, the standard normal distribution has a standard deviation of
exactly 1.
5. According to the Empirical Rule, approximately what percentage of data falls
within one standard deviation of the mean in a normal distribution?
A. 50%
B. 68%
C. 99.7%
D. 95%
Answer: B
Rationale: The Empirical Rule states that 68% of data falls within 1 standard deviation,
95% within 2, and 99.7% within 3.
, 6. What does a Z-score of +2.0 indicate?
A. The value is 2 units above the mean.
B. The value is twice the size of the mean.
C. The value is 2% higher than the mean.
D. The value is 2 standard deviations above the mean.
Answer: D
Rationale: A Z-score measures the number of standard deviations a data point is from the
mean.
7. The Law of Large Numbers states that as the sample size increases:
A. The standard deviation increases.
B. The sample mean gets closer to the population mean.
C. The data becomes more skewed.
D. The sample mean becomes exactly zero.
Answer: B
Rationale: As sample size increases, the empirical probability (sample mean) converges
toward the theoretical probability (population mean).
8. The Central Limit Theorem states that the sampling distribution of the mean
will be approximately normal if:
A. The sample size is large enough (usually n > 30).
B. The population is small.
C. The data is categorical.
D. The standard deviation is zero.
Answer: A
Rationale: The Central Limit Theorem applies when the sample size is sufficiently large,
typically n > 30, regardless of the population’s distribution shape.
1. What is the sum of the probabilities of all possible outcomes in a sample
space?
A. 1.0
B. 0.5
C. 0.0
D. 100
Answer: A
Rationale: In any probability distribution, the sum of all possible outcomes must equal 1.0
(or 100%).
2. Which of the following describes two events that cannot occur at the same
time?
A. Mutually exclusive events
B. Dependent events
C. Independent events
D. Conditional events
Answer: A
Rationale: Mutually exclusive events (or disjoint events) are events that cannot happen
simultaneously.
,3. In a standard normal distribution, what is the mean?
A. 1
B. 0.5
C. 10
D. 0
Answer: D
Rationale: The standard normal distribution (Z-distribution) always has a mean of 0 and a
standard deviation of 1.
4. In a standard normal distribution, what is the standard deviation?
A. 0
B. 1
C. 0.5
D. Variable
Answer: B
Rationale: By definition, the standard normal distribution has a standard deviation of
exactly 1.
5. According to the Empirical Rule, approximately what percentage of data falls
within one standard deviation of the mean in a normal distribution?
A. 50%
B. 68%
C. 99.7%
D. 95%
Answer: B
Rationale: The Empirical Rule states that 68% of data falls within 1 standard deviation,
95% within 2, and 99.7% within 3.
, 6. What does a Z-score of +2.0 indicate?
A. The value is 2 units above the mean.
B. The value is twice the size of the mean.
C. The value is 2% higher than the mean.
D. The value is 2 standard deviations above the mean.
Answer: D
Rationale: A Z-score measures the number of standard deviations a data point is from the
mean.
7. The Law of Large Numbers states that as the sample size increases:
A. The standard deviation increases.
B. The sample mean gets closer to the population mean.
C. The data becomes more skewed.
D. The sample mean becomes exactly zero.
Answer: B
Rationale: As sample size increases, the empirical probability (sample mean) converges
toward the theoretical probability (population mean).
8. The Central Limit Theorem states that the sampling distribution of the mean
will be approximately normal if:
A. The sample size is large enough (usually n > 30).
B. The population is small.
C. The data is categorical.
D. The standard deviation is zero.
Answer: A
Rationale: The Central Limit Theorem applies when the sample size is sufficiently large,
typically n > 30, regardless of the population’s distribution shape.
