NSL 503 Module 3 Statistics Nursing Exam
2026/2027 – Questions and Answers | 100%
Verified | Detailed Rationales – Pass
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1. A nurse researcher is analyzing the average waiting time for patients in an
emergency department. Which measure of central tendency is most
appropriate for this data, which may contain a few extremely long wait
times?
o A. Mean
o B. Median
o C. Mode
o D. Range
Correct Answer: B. Median
Rationale: The median is the most appropriate measure of central tendency
when a dataset contains outliers or is skewed. The mean is sensitive to extreme
values (like a few very long wait times), which would pull its value upward and
misrepresent the "typical" wait time. The median, being the middle value, is not
affected by these outliers. The mode is used for categorical data, and the range is
a measure of dispersion, not central tendency.
2. A study reports a p-value of 0.03. Using a standard significance level (alpha)
of 0.05, what is the correct interpretation of this result?
o A. There is a 3% chance the null hypothesis is true.
o B. There is a 3% chance the results are due to random error.
o C. The null hypothesis should be rejected.
, o D. The null hypothesis should be accepted.
Correct Answer: C. The null hypothesis should be rejected.
Rationale: The p-value is the probability of observing the study results (or
more extreme results) if the null hypothesis were true. A common threshold for
significance is alpha = 0.05. If the p-value (0.03) is less than or equal to alpha
(0.05), the result is considered statistically significant, and we reject the null
hypothesis. It does not mean there is a 3% chance the null is true; it means that if
the null were true, we would see these results only 3% of the time by chance.
3. Which of the following is a measure of dispersion that describes the
average distance of each data point from the mean?
o A. Range
o B. Interquartile Range (IQR)
o C. Variance
o D. Standard Deviation
Correct Answer: D. Standard Deviation
Rationale: The standard deviation is the square root of the variance and is
expressed in the same units as the original data. It represents the typical or
average distance of individual data points from the mean. The range is the
difference between the highest and lowest values. The IQR describes the spread
of the middle 50% of the data. Variance is the average of the squared differences
from the mean, but its units are squared, making it less intuitive to interpret than
the standard deviation.
4. A nurse is studying the relationship between smoking (yes/no) and the
presence of a chronic cough (yes/no). Which statistical test is most
appropriate to analyze this relationship?
o A. Independent samples t-test
o B. Chi-square test
o C. Pearson correlation
, o D. ANOVA
Correct Answer: B. Chi-square test
Rationale: The Chi-square test of independence is used to determine if there
is a significant association between two categorical variables. In this case, both
"smoking status" and "presence of a chronic cough" are categorical (nominal)
variables. The t-test and ANOVA are used for comparing means of continuous
variables. Pearson correlation is used for the relationship between two continuous
variables.
5. In a study with 50 participants, a nurse calculates the mean systolic blood
pressure to be 120 mmHg with a standard deviation of 10 mmHg. Assuming
a normal distribution, approximately what percentage of participants would
have a systolic blood pressure between 110 and 130 mmHg?
o A. 50%
o B. 68%
o C. 95%
o D. 99.7%
Correct Answer: B. 68%
Rationale: The empirical rule (or 68-95-99.7 rule) applies to normal
distributions. It states that approximately 68% of the data falls within one
standard deviation of the mean. Here, the mean is 120 and the standard deviation
is 10. The range 110 to 130 mmHg represents one standard deviation above and
below the mean (120 ± 10). Therefore, approximately 68% of the participants
would fall within this range.
6. A Type I error in statistical hypothesis testing occurs when:
o A. The null hypothesis is true, and we fail to reject it.
o B. The null hypothesis is false, and we fail to reject it.
o C. The null hypothesis is true, and we reject it.
, o D. The null hypothesis is false, and we reject it.
Correct Answer: C. The null hypothesis is true, and we reject it.
Rationale: A Type I error, also known as a "false positive," occurs when a
researcher incorrectly rejects a true null hypothesis. The probability of making a
Type I error is denoted by alpha (α), which is the significance level. Option B
describes a Type II error (a "false negative"), and Option D is a correct decision
(power).
7. A nurse wants to compare the mean pain scores (on a 0-10 scale) of three
different groups of patients receiving different pain management
interventions. Which statistical test should be used?
o A. Paired t-test
o B. Independent samples t-test
o C. One-way ANOVA
o D. Chi-square test
Correct Answer: C. One-way ANOVA
Rationale: One-way Analysis of Variance (ANOVA) is used to compare the
means of three or more independent groups. The independent samples t-test is
only for comparing the means of two groups. The paired t-test is for comparing
means from the same group at two different times or under two different
conditions. The Chi-square test is for categorical data.
8. The power of a statistical test is the probability of:
o A. Rejecting a true null hypothesis.
o B. Failing to reject a false null hypothesis.
o C. Rejecting a false null hypothesis.
o D. Failing to reject a true null hypothesis.
Correct Answer: C. Rejecting a false null hypothesis.
Rationale: Power is the ability of a test to detect an effect when there is one.
2026/2027 – Questions and Answers | 100%
Verified | Detailed Rationales – Pass
Guaranteed – A+ Graded
1. A nurse researcher is analyzing the average waiting time for patients in an
emergency department. Which measure of central tendency is most
appropriate for this data, which may contain a few extremely long wait
times?
o A. Mean
o B. Median
o C. Mode
o D. Range
Correct Answer: B. Median
Rationale: The median is the most appropriate measure of central tendency
when a dataset contains outliers or is skewed. The mean is sensitive to extreme
values (like a few very long wait times), which would pull its value upward and
misrepresent the "typical" wait time. The median, being the middle value, is not
affected by these outliers. The mode is used for categorical data, and the range is
a measure of dispersion, not central tendency.
2. A study reports a p-value of 0.03. Using a standard significance level (alpha)
of 0.05, what is the correct interpretation of this result?
o A. There is a 3% chance the null hypothesis is true.
o B. There is a 3% chance the results are due to random error.
o C. The null hypothesis should be rejected.
, o D. The null hypothesis should be accepted.
Correct Answer: C. The null hypothesis should be rejected.
Rationale: The p-value is the probability of observing the study results (or
more extreme results) if the null hypothesis were true. A common threshold for
significance is alpha = 0.05. If the p-value (0.03) is less than or equal to alpha
(0.05), the result is considered statistically significant, and we reject the null
hypothesis. It does not mean there is a 3% chance the null is true; it means that if
the null were true, we would see these results only 3% of the time by chance.
3. Which of the following is a measure of dispersion that describes the
average distance of each data point from the mean?
o A. Range
o B. Interquartile Range (IQR)
o C. Variance
o D. Standard Deviation
Correct Answer: D. Standard Deviation
Rationale: The standard deviation is the square root of the variance and is
expressed in the same units as the original data. It represents the typical or
average distance of individual data points from the mean. The range is the
difference between the highest and lowest values. The IQR describes the spread
of the middle 50% of the data. Variance is the average of the squared differences
from the mean, but its units are squared, making it less intuitive to interpret than
the standard deviation.
4. A nurse is studying the relationship between smoking (yes/no) and the
presence of a chronic cough (yes/no). Which statistical test is most
appropriate to analyze this relationship?
o A. Independent samples t-test
o B. Chi-square test
o C. Pearson correlation
, o D. ANOVA
Correct Answer: B. Chi-square test
Rationale: The Chi-square test of independence is used to determine if there
is a significant association between two categorical variables. In this case, both
"smoking status" and "presence of a chronic cough" are categorical (nominal)
variables. The t-test and ANOVA are used for comparing means of continuous
variables. Pearson correlation is used for the relationship between two continuous
variables.
5. In a study with 50 participants, a nurse calculates the mean systolic blood
pressure to be 120 mmHg with a standard deviation of 10 mmHg. Assuming
a normal distribution, approximately what percentage of participants would
have a systolic blood pressure between 110 and 130 mmHg?
o A. 50%
o B. 68%
o C. 95%
o D. 99.7%
Correct Answer: B. 68%
Rationale: The empirical rule (or 68-95-99.7 rule) applies to normal
distributions. It states that approximately 68% of the data falls within one
standard deviation of the mean. Here, the mean is 120 and the standard deviation
is 10. The range 110 to 130 mmHg represents one standard deviation above and
below the mean (120 ± 10). Therefore, approximately 68% of the participants
would fall within this range.
6. A Type I error in statistical hypothesis testing occurs when:
o A. The null hypothesis is true, and we fail to reject it.
o B. The null hypothesis is false, and we fail to reject it.
o C. The null hypothesis is true, and we reject it.
, o D. The null hypothesis is false, and we reject it.
Correct Answer: C. The null hypothesis is true, and we reject it.
Rationale: A Type I error, also known as a "false positive," occurs when a
researcher incorrectly rejects a true null hypothesis. The probability of making a
Type I error is denoted by alpha (α), which is the significance level. Option B
describes a Type II error (a "false negative"), and Option D is a correct decision
(power).
7. A nurse wants to compare the mean pain scores (on a 0-10 scale) of three
different groups of patients receiving different pain management
interventions. Which statistical test should be used?
o A. Paired t-test
o B. Independent samples t-test
o C. One-way ANOVA
o D. Chi-square test
Correct Answer: C. One-way ANOVA
Rationale: One-way Analysis of Variance (ANOVA) is used to compare the
means of three or more independent groups. The independent samples t-test is
only for comparing the means of two groups. The paired t-test is for comparing
means from the same group at two different times or under two different
conditions. The Chi-square test is for categorical data.
8. The power of a statistical test is the probability of:
o A. Rejecting a true null hypothesis.
o B. Failing to reject a false null hypothesis.
o C. Rejecting a false null hypothesis.
o D. Failing to reject a true null hypothesis.
Correct Answer: C. Rejecting a false null hypothesis.
Rationale: Power is the ability of a test to detect an effect when there is one.
