LATEST BIOSTATISTICS COMPLETE EXAM QUESTIONS AND
ANSWERS WITH VERIFIED RATIONALES.
1. Which of the following best describes biostatistics?
A. The study of biological organisms
B. The application of statistical methods to biological data
C. The study of probability distributions only
D. The measurement of clinical outcomes without analysis
Correct Answer: B
Rationale: Biostatistics involves applying statistical techniques to biological and
health-related data. The other options are either too narrow or incorrect.
2. A variable that can take any value within a range is known as:
A. Discrete variable
B. Continuous variable
C. Categorical variable
D. Nominal variable
Correct Answer: B
Rationale: Continuous variables can take any value within a given range, unlike
discrete variables which take specific values only.
3. Which measure of central tendency is most affected by extreme values?
A. Median
B. Mode
C. Mean
D. Range
Correct Answer: C
Rationale: The mean is sensitive to outliers, while median and mode are more robust.
4. The standard deviation measures:
A. Central tendency
B. Spread of data around the mean
C. The largest value in a dataset
D. Correlation between variables
Correct Answer: B
Rationale: Standard deviation quantifies variability or dispersion around the mean.
5. Which scale of measurement includes true zero?
A. Nominal
B. Ordinal
C. Interval
, D. Ratio
Correct Answer: D
Rationale: Ratio scale has a true zero, allowing meaningful ratio comparisons.
6. In a normal distribution, what percentage of data lies within ±1 standard deviation?
A. 50%
B. 68%
C. 75%
D. 95%
Correct Answer: B
Rationale: Approximately 68% of observations lie within one standard deviation in a
normal distribution.
7. Which test is used to compare means between two independent groups?
A. Paired t-test
B. Chi-square test
C. Independent t-test
D. ANOVA
Correct Answer: C
Rationale: Independent t-test compares means between two unrelated groups.
8. A p-value less than 0.05 typically indicates:
A. Strong evidence against the null hypothesis
B. The null hypothesis is true
C. Data is normally distributed
D. No association exists
Correct Answer: A
Rationale: A small p-value suggests rejecting the null hypothesis.
9. Type I error refers to:
A. Failing to reject a false null hypothesis
B. Rejecting a true null hypothesis
C. Incorrect data collection
D. Measurement bias
Correct Answer: B
Rationale: Type I error is a false positive—rejecting a true null hypothesis.
10. Which statistical test is appropriate for categorical data?
A. t-test
B. ANOVA
, C. Chi-square test
D. Regression
Correct Answer: C
Rationale: Chi-square test is used for categorical variables.
11. The median is defined as:
A. Most frequent value
B. Middle value of ordered data
C. Average of values
D. Difference between values
Correct Answer: B
Rationale: Median is the central value when data is arranged in order.
12. What is the range of a dataset?
A. Mean value
B. Median value
C. Difference between maximum and minimum
D. Standard deviation
Correct Answer: C
Rationale: Range measures spread as max minus min.
13. A skewed distribution has:
A. Symmetry
B. No variation
C. Asymmetry
D. Equal mean and median
Correct Answer: C
Rationale: Skewness refers to asymmetry in data distribution.
14. In hypothesis testing, the null hypothesis usually states:
A. There is a difference
B. There is no effect or difference
C. Data is skewed
D. Sample size is large
Correct Answer: B
Rationale: The null hypothesis assumes no effect or relationship.
15. Which measure is most appropriate for skewed data?
A. Mean
B. Median
, C. Standard deviation
D. Variance
Correct Answer: B
Rationale: Median is less affected by skewness and outliers.
16. A confidence interval provides:
A. Exact population value
B. Range of plausible values for a parameter
C. Probability of hypothesis
D. Sample mean only
Correct Answer: B
Rationale: Confidence intervals estimate where the population parameter lies.
17. Which test compares more than two group means?
A. t-test
B. ANOVA
C. Chi-square
D. Correlation
Correct Answer: B
Rationale: ANOVA is used for comparing means across multiple groups.
18. Correlation coefficient ranges between:
A. 0 to 1
B. -1 to +1
C. 0 to 100
D. -100 to +100
Correct Answer: B
Rationale: Correlation values range from -1 to +1 indicating direction and strength.
19. A positive correlation means:
A. One variable decreases as the other increases
B. Both variables increase together
C. No relationship exists
D. Variables are independent
Correct Answer: B
Rationale: Positive correlation indicates both variables move in the same direction.
20. Which study design is best for determining causality?
A. Cross-sectional
B. Case-control
ANSWERS WITH VERIFIED RATIONALES.
1. Which of the following best describes biostatistics?
A. The study of biological organisms
B. The application of statistical methods to biological data
C. The study of probability distributions only
D. The measurement of clinical outcomes without analysis
Correct Answer: B
Rationale: Biostatistics involves applying statistical techniques to biological and
health-related data. The other options are either too narrow or incorrect.
2. A variable that can take any value within a range is known as:
A. Discrete variable
B. Continuous variable
C. Categorical variable
D. Nominal variable
Correct Answer: B
Rationale: Continuous variables can take any value within a given range, unlike
discrete variables which take specific values only.
3. Which measure of central tendency is most affected by extreme values?
A. Median
B. Mode
C. Mean
D. Range
Correct Answer: C
Rationale: The mean is sensitive to outliers, while median and mode are more robust.
4. The standard deviation measures:
A. Central tendency
B. Spread of data around the mean
C. The largest value in a dataset
D. Correlation between variables
Correct Answer: B
Rationale: Standard deviation quantifies variability or dispersion around the mean.
5. Which scale of measurement includes true zero?
A. Nominal
B. Ordinal
C. Interval
, D. Ratio
Correct Answer: D
Rationale: Ratio scale has a true zero, allowing meaningful ratio comparisons.
6. In a normal distribution, what percentage of data lies within ±1 standard deviation?
A. 50%
B. 68%
C. 75%
D. 95%
Correct Answer: B
Rationale: Approximately 68% of observations lie within one standard deviation in a
normal distribution.
7. Which test is used to compare means between two independent groups?
A. Paired t-test
B. Chi-square test
C. Independent t-test
D. ANOVA
Correct Answer: C
Rationale: Independent t-test compares means between two unrelated groups.
8. A p-value less than 0.05 typically indicates:
A. Strong evidence against the null hypothesis
B. The null hypothesis is true
C. Data is normally distributed
D. No association exists
Correct Answer: A
Rationale: A small p-value suggests rejecting the null hypothesis.
9. Type I error refers to:
A. Failing to reject a false null hypothesis
B. Rejecting a true null hypothesis
C. Incorrect data collection
D. Measurement bias
Correct Answer: B
Rationale: Type I error is a false positive—rejecting a true null hypothesis.
10. Which statistical test is appropriate for categorical data?
A. t-test
B. ANOVA
, C. Chi-square test
D. Regression
Correct Answer: C
Rationale: Chi-square test is used for categorical variables.
11. The median is defined as:
A. Most frequent value
B. Middle value of ordered data
C. Average of values
D. Difference between values
Correct Answer: B
Rationale: Median is the central value when data is arranged in order.
12. What is the range of a dataset?
A. Mean value
B. Median value
C. Difference between maximum and minimum
D. Standard deviation
Correct Answer: C
Rationale: Range measures spread as max minus min.
13. A skewed distribution has:
A. Symmetry
B. No variation
C. Asymmetry
D. Equal mean and median
Correct Answer: C
Rationale: Skewness refers to asymmetry in data distribution.
14. In hypothesis testing, the null hypothesis usually states:
A. There is a difference
B. There is no effect or difference
C. Data is skewed
D. Sample size is large
Correct Answer: B
Rationale: The null hypothesis assumes no effect or relationship.
15. Which measure is most appropriate for skewed data?
A. Mean
B. Median
, C. Standard deviation
D. Variance
Correct Answer: B
Rationale: Median is less affected by skewness and outliers.
16. A confidence interval provides:
A. Exact population value
B. Range of plausible values for a parameter
C. Probability of hypothesis
D. Sample mean only
Correct Answer: B
Rationale: Confidence intervals estimate where the population parameter lies.
17. Which test compares more than two group means?
A. t-test
B. ANOVA
C. Chi-square
D. Correlation
Correct Answer: B
Rationale: ANOVA is used for comparing means across multiple groups.
18. Correlation coefficient ranges between:
A. 0 to 1
B. -1 to +1
C. 0 to 100
D. -100 to +100
Correct Answer: B
Rationale: Correlation values range from -1 to +1 indicating direction and strength.
19. A positive correlation means:
A. One variable decreases as the other increases
B. Both variables increase together
C. No relationship exists
D. Variables are independent
Correct Answer: B
Rationale: Positive correlation indicates both variables move in the same direction.
20. Which study design is best for determining causality?
A. Cross-sectional
B. Case-control
