HLTH 644 Quiz 7: Finding Normal | Module 7
Week 7 | Questions and Answers | 2026/2027
Updated | 100% Correct - Liberty University
Practice Question Bank & Answer Rationale
THIS PACK CONTAINS
50 exam-style multiple-choice questions. Each question includes the correct answer and a complete rationale
for focused revision.
COVERAGE
This quiz assesses graduate-level understanding of normal distributions, z-scores, probability, sampling
distributions, and the Central Limit Theorem as applied to health sciences data. It emphasizes interpretation
of clinical measurements, reference ranges, and statistical inference in public health research.
STUDY GUIDE
Recommended duration: 75 minutes. Passing target: 80%.
HIGHP - Page 1 of 18
,1. A patient's systolic blood pressure is recorded as 142 mmHg. The population mean is
120 mmHg with a standard deviation of 15 mmHg. What is the z-score for this
measurement?
[ ] A. 1.47
[ ] B. 1.50
[ ] C. 1.53
[ ] D. 1.56
CORRECT: A. 1.47
The z-score is calculated as (142 - 120) / 15 = 1.47. This indicates the value is 1.47 standard
deviations above the mean. The other options result from arithmetic errors or using incorrect means.
2. In a study of serum cholesterol, the distribution is approximately normal with mean 200
mg/dL and standard deviation 30 mg/dL. What proportion of the population has
cholesterol between 170 and 230 mg/dL?
[ ] A. 0.6827
[ ] B. 0.9545
[ ] C. 0.9973
[ ] D. 0.5000
CORRECT: A. 0.6827
The interval 170-230 mg/dL corresponds to ±1 standard deviation from the mean. By the empirical rule,
approximately 68.27% of a normal distribution lies within one standard deviation. The other options represent
±2 SD (95.45%), ±3 SD (99.73%), and half the distribution.
3. A public health researcher collects a sample of 100 individuals and calculates the
sample mean BMI. If the population standard deviation is 5, what is the standard error of
the mean?
[ ] A. 0.05
[ ] B. 0.50
[ ] C. 5.00
[ ] D. 0.10
CORRECT: B. 0.50
Standard error = /n = 5/100 = 5/10 = 0.50. This quantifies the variability of sample means around the
population mean. Options A, C, and D misapply the formula or confuse standard deviation with standard
error.
HIGHP - Page 2 of 18
, 4. Which statement correctly describes the Central Limit Theorem (CLT) as it applies to
health research?
[ ] A. The sampling distribution of the mean approaches normality as sample size increases, regardless
of population distribution.
[ ] B. The population distribution must be normal for the CLT to apply.
[ ] C. The CLT states that sample means will always equal the population mean.
[ ] D. The CLT requires the sample size to be less than 30.
CORRECT: A. The sampling distribution of the mean approaches normality as sample size increases,
regardless of population distribution.
The CLT states that for large sample sizes, the sampling distribution of the mean approximates a normal
distribution even if the population is not normal. Option B is incorrect because normality of the population is
not required. Option C confuses the mean of sample means with individual sample means. Option D is the
opposite of the CLT's requirement.
5. A diagnostic test uses a cutoff at the 95th percentile of a normal distribution of
biomarker values. What is the z-score corresponding to this cutoff?
[ ] A. 1.645
[ ] B. 1.960
[ ] C. 2.326
[ ] D. 1.282
CORRECT: A. 1.645
The 95th percentile corresponds to a z-score of approximately 1.645. This is the one-tailed critical value for a
5% upper tail. Option B is for a two-tailed 95% confidence interval, Option C for 99th percentile, and Option D
for 90th percentile.
6. In a clinical trial, the mean reduction in blood pressure is 10 mmHg with a standard
error of 2 mmHg. What is the 95% confidence interval for the mean reduction?
[ ] A. (6.08, 13.92)
[ ] B. (8.00, 12.00)
[ ] C. (5.00, 15.00)
[ ] D. (7.04, 12.96)
CORRECT: A. (6.08, 13.92)
The 95% CI is mean ± 1.96 × SE = 10 ± 1.96 × 2 = 10 ± 3.92, yielding (6.08, 13.92). Option B uses ±1 SE,
Option C uses ±2.5 SE, and Option D uses ±1.48 SE, which are incorrect multipliers.
HIGHP - Page 3 of 18
Week 7 | Questions and Answers | 2026/2027
Updated | 100% Correct - Liberty University
Practice Question Bank & Answer Rationale
THIS PACK CONTAINS
50 exam-style multiple-choice questions. Each question includes the correct answer and a complete rationale
for focused revision.
COVERAGE
This quiz assesses graduate-level understanding of normal distributions, z-scores, probability, sampling
distributions, and the Central Limit Theorem as applied to health sciences data. It emphasizes interpretation
of clinical measurements, reference ranges, and statistical inference in public health research.
STUDY GUIDE
Recommended duration: 75 minutes. Passing target: 80%.
HIGHP - Page 1 of 18
,1. A patient's systolic blood pressure is recorded as 142 mmHg. The population mean is
120 mmHg with a standard deviation of 15 mmHg. What is the z-score for this
measurement?
[ ] A. 1.47
[ ] B. 1.50
[ ] C. 1.53
[ ] D. 1.56
CORRECT: A. 1.47
The z-score is calculated as (142 - 120) / 15 = 1.47. This indicates the value is 1.47 standard
deviations above the mean. The other options result from arithmetic errors or using incorrect means.
2. In a study of serum cholesterol, the distribution is approximately normal with mean 200
mg/dL and standard deviation 30 mg/dL. What proportion of the population has
cholesterol between 170 and 230 mg/dL?
[ ] A. 0.6827
[ ] B. 0.9545
[ ] C. 0.9973
[ ] D. 0.5000
CORRECT: A. 0.6827
The interval 170-230 mg/dL corresponds to ±1 standard deviation from the mean. By the empirical rule,
approximately 68.27% of a normal distribution lies within one standard deviation. The other options represent
±2 SD (95.45%), ±3 SD (99.73%), and half the distribution.
3. A public health researcher collects a sample of 100 individuals and calculates the
sample mean BMI. If the population standard deviation is 5, what is the standard error of
the mean?
[ ] A. 0.05
[ ] B. 0.50
[ ] C. 5.00
[ ] D. 0.10
CORRECT: B. 0.50
Standard error = /n = 5/100 = 5/10 = 0.50. This quantifies the variability of sample means around the
population mean. Options A, C, and D misapply the formula or confuse standard deviation with standard
error.
HIGHP - Page 2 of 18
, 4. Which statement correctly describes the Central Limit Theorem (CLT) as it applies to
health research?
[ ] A. The sampling distribution of the mean approaches normality as sample size increases, regardless
of population distribution.
[ ] B. The population distribution must be normal for the CLT to apply.
[ ] C. The CLT states that sample means will always equal the population mean.
[ ] D. The CLT requires the sample size to be less than 30.
CORRECT: A. The sampling distribution of the mean approaches normality as sample size increases,
regardless of population distribution.
The CLT states that for large sample sizes, the sampling distribution of the mean approximates a normal
distribution even if the population is not normal. Option B is incorrect because normality of the population is
not required. Option C confuses the mean of sample means with individual sample means. Option D is the
opposite of the CLT's requirement.
5. A diagnostic test uses a cutoff at the 95th percentile of a normal distribution of
biomarker values. What is the z-score corresponding to this cutoff?
[ ] A. 1.645
[ ] B. 1.960
[ ] C. 2.326
[ ] D. 1.282
CORRECT: A. 1.645
The 95th percentile corresponds to a z-score of approximately 1.645. This is the one-tailed critical value for a
5% upper tail. Option B is for a two-tailed 95% confidence interval, Option C for 99th percentile, and Option D
for 90th percentile.
6. In a clinical trial, the mean reduction in blood pressure is 10 mmHg with a standard
error of 2 mmHg. What is the 95% confidence interval for the mean reduction?
[ ] A. (6.08, 13.92)
[ ] B. (8.00, 12.00)
[ ] C. (5.00, 15.00)
[ ] D. (7.04, 12.96)
CORRECT: A. (6.08, 13.92)
The 95% CI is mean ± 1.96 × SE = 10 ± 1.96 × 2 = 10 ± 3.92, yielding (6.08, 13.92). Option B uses ±1 SE,
Option C uses ±2.5 SE, and Option D uses ±1.48 SE, which are incorrect multipliers.
HIGHP - Page 3 of 18
