# 50+ Solved Basic Biostatistics MCQs with Answers

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This collection of Biostatistics MCQs will help you to assess your understanding of key biostatistical concepts. Biostatistics MCQs are an essential tool for medical students, as it allows them to analyse and interpret data in order to make informed decisions about patient care.

## Biostatistics MCQs Topics

• Descriptive Statistics
• Graphical Data Summary
• Sampling
• Statistical Comparison of Groups
• Correlation and Regression

### Biostatistics MCQs On Descriptive Statistics

1.What is the measure of central tendency that is most influenced by outliers?
A. Mean
B. Median
C. Mode
D. Range

2. Which of the following is a measure of variability?

A. Median
B. Range
C. Mode
D. Mean

3. In a normal distribution, what percentage of data falls within one standard deviation from the mean?

A. 68%
B. 75%
C. 95%
D. 99%

4. If a dataset has an even number of observations, how is the median calculated?

A. Average of the two middle values
B. The middle value
C. Sum of all values divided by the number of observations
D. None of the above

5. Which of the following is not a measure of central tendency?

A. Mean
B. Median
C. Range
D. Mode

6. What does the interquartile range (IQR) represent?

A. The range between the maximum and minimum values
B. The range between the first and third quartiles
C. The range between the mean and median
D. The range between the mode and median

7. If a dataset has a positively skewed distribution, where is the tail of the distribution located?

A. Left
B. Right
C. Center
D. None of the above

8. Which of the following is a measure of the spread of a distribution?

A. Mean
B. Median
C. Variance
D. Mode

9. In a box-and-whisker plot, which part of the box represents the interquartile range (IQR)?

A. The entire box
B. The middle 50% of the box
C. The top and bottom edges of the box
D. The whiskers

10. What does the standard deviation measure in a dataset?

A. The average value
B. The spread of values around the mean
C. The most frequent value
D. The difference between the largest and smallest values

### Biostatistics MCQs On Graphical Data Summary

11.Which graphical representation is best suited for displaying the distribution of a continuous variable in biostatistics?

A. Pie chart
B. Histogram
C. Bar graph
D. Line chart

12.In a box-and-whisker plot, what does the box represent?

A. Interquartile range (IQR)
B. Mean
C. Median
D. Standard deviation

13.What type of graph is commonly used to display the relationship between two continuous variables in biostatistics?

A. Scatter plot
B. Bar graph
C. Line chart
D. Histogram

14.Which graphical representation is suitable for displaying the distribution of categorical data in different groups?

A. Histogram
B. Box plot
C. Bar chart
D. Line graph

15.What does a cumulative frequency plot show in biostatistics?

A. The frequency of each category
B. The cumulative sum of frequencies
C. The range of the data
D. The mean and standard deviation

16.In a bar chart, what does the height of each bar represent?

A. Mean
B. Median
C. Frequency
D. Standard deviation

17.Which graph is used to visualize the relationship between three variables in biostatistics?

A. Scatter plot
B. Pie chart
C. 3D plot
D. Histogram

18.What does a radar chart in biostatistics represent?

A. Distribution of data
B. Relationship between variables
C. Comparison of multiple groups
D. Cumulative frequency

19.In a line chart, what is typically represented on the x-axis?

A. Frequency
B. Categories
C. Time or a continuous variable
D. Cumulative frequency

20.What is the primary purpose of a pie chart in biostatistics?

A. Displaying the distribution of a continuous variable
B. Showing the relationship between two variables
C. Representing the parts of a whole
D. Comparing the mean and median

### Biostatistics MCQs On Sampling

21.What is the main goal of random sampling in biostatistics?

A. Reduce bias
B. Represent the entire population
C. Simplify the sampling process
D. Include specific groups only

22.Which sampling method is most likely to introduce bias in a biostatistical study?

A. Random sampling
B. Stratified sampling
C. Convenience sampling
D. Cluster sampling

23.What is systematic sampling in biostatistics?

A. Randomly selecting individuals from different strata
B. Choosing every nth individual from a list
C. Selecting individuals based on convenience
D. Collecting data from a specific group

24.Advantage of using stratified sampling in biostatistics?

A. Reduces sampling bias
B. Ensures every individual has an equal chance of being selected
C. Simplifies the sampling process
D. Increases variability in the sample

25.In cluster sampling, what is a cluster?

A. A group of individuals with similar characteristics
B. A subgroup within a stratum
C. A randomly selected subset of the population
D. A naturally occurring group in the population

26.Purpose of convenience sampling in biostatistics?

A. Ensure a representative sample
B. Reduce bias in the sample
C. Make the sampling process convenient for researchers
D. Include all possible individuals in the sample

27.Disadvantage of using simple random sampling?

A. Time-consuming
B. May not ensure representation of all groups
C. Introduces bias
D. Requires extensive resources

28.What is non-probability sampling in biostatistics?

A. Sampling where each individual has an equal chance of being selected
B. Sampling without considering the probability of selection
C. Sampling based on predetermined quotas
D. Sampling that ensures representation of all strata

29.Disadvantage of using quota sampling in biostatistics?

A. May introduce bias
B. Time-consuming
C. Requires a large sample size
D. Ensures representation of all groups

30.What does it mean if a sample is representative in biostatistics?

A. Includes individuals from specific groups
B. Accurately reflects the characteristics of the entire population
C. Is a small subset of the population
D. Chosen through convenience sampling

### Biostatistics MCQs On Statistical Comparison of Groups

31.Which statistical test is appropriate for comparing the means of two independent groups?

A. t-test
B. ANOVA
C. Chi-square test
D. Mann-Whitney U test

32.When comparing the means of three or more groups, which statistical test is commonly used?

A. t-test
B. ANOVA
C. Wilcoxon signed-rank test
D. Kruskal-Wallis test

33.Which of the following is a parametric test for comparing the means of two paired groups?

A. Independent samples t-test
B. Paired samples t-test
C. Mann-Whitney U test
D. Chi-square test

34.In a one-way ANOVA, what does the F-statistic measure?

A. Difference between group means
B. Variability within groups
C. Variability between groups
D. Overall mean of the groups

35.When should the non-parametric Kruskal-Wallis test be used instead of one-way ANOVA?

A. When the assumption of normality is violated
B. When there are only two groups to compare
C. When the data is categorical
D. When the data is ordinal

Read Also >> Basic Statistical Inference MCQs

36.Which statistical test is suitable for comparing proportions between two independent groups?

A. t-test
B. ANOVA
C. Chi-square test
D. Fisher’s exact test

37.What does the p-value in hypothesis testing indicate?

A. The effect size
B. The probability of observing the data if the null hypothesis is true
C. The margin of error
D. The power of the test

38.In a Mann-Whitney U test, what is being compared between two independent groups?

A. Means
B. Medians
C. Variances
D. Proportions

39.What is the purpose of post-hoc tests in ANOVA?

A. To check for outliers in the data
B. To explore pairwise differences between groups
C. To calculate effect size
D. To assess normality assumptions

40.When should a Bonferroni correction be applied in statistical testing?

A. To increase the power of the test
B. When conducting multiple hypothesis tests
C. When the sample size is small
D. When the p-value is large

### Biostatistics MCQs On Correlation and Regression

41.What does a correlation coefficient measure in biostatistics?

A. Causation between variables
B. Strength and direction of a linear relationship
C. Mean of the variables
D. Variability within a variable

42.In a scatter plot, what does the slope of the regression line represent?

A. Correlation coefficient
B. Intercept
C. Standard deviation
D. Rate of change

43.What does a positive correlation coefficient indicate?

A. No relationship between variables
B. A strong negative linear relationship
C. A strong positive linear relationship
D. Perfect correlation

44.In regression analysis, what is the dependent variable?

A. Predictor variable
B. Outcome variable
C. Confounding variable
D. Covariate

45.What does the coefficient of determination (R-squareD. represent?

A. Strength of the relationship
B. Proportion of variability explained by the model
C. Direction of the relationship
D. Standard error of the estimate

46.If the correlation coefficient is -0.75, what type of relationship exists between the variables?

A. Strong positive
B. Strong negative
C. Weak positive
D. No relationship

47.What is the purpose of a residual plot in regression analysis?

A. To check for outliers
B. To assess normality assumptions
C. To visualize the relationship between variables
D. To examine the homoscedasticity of residuals

48.What is the range of values for a correlation coefficient?

A. -1 to 1
B. 0 to 1
C. 1 to 100
D. -100 to 100

49.In multiple regression, how many independent variables are considered?

A. One
B. Two
C. Three or more
D. None

50.If the p-value for the correlation coefficient is 0.03, what does this suggest about the relationship?

A. The relationship is significant
B. The relationship is not significant
C. The correlation is perfect
D. The sample size is too small

The field of biostatistics combines biology, statistics, and medical research. In essence, it is the study of data analysis and interpretation in the biological sciences utilising statistical techniques. Below is a summary of the main ideas: