Introduction to Statistics and Biostatistics MCQs With Answer

Introduction to Statistics and Biostatistics MCQs With Answer

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Introduction to Statistics and Biostatistics MCQs With Answer provides B. Pharm students with clear, practical practice on core topics in statistics and biostatistics essential for pharmacy studies. It covers descriptive statistics (mean, median, mode, standard deviation), probability distributions, hypothesis testing (p-value, Type I/II errors), confidence intervals, sample size, and analytical methods used in pharmacology and clinical trials. Emphasis is on data interpretation, study design, diagnostic test evaluation (sensitivity, specificity, ROC), and basic survival and regression analyses. Each MCQ helps build competence in data analysis, critical appraisal, and research reporting for pharmacists. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What best distinguishes biostatistics from general statistics?

  • Biostatistics focuses on applying statistical methods to biological and health sciences
  • Biostatistics only uses non-parametric methods
  • Statistics cannot be used in clinical research
  • Biostatistics ignores probability theory

Correct Answer: Biostatistics focuses on applying statistical methods to biological and health sciences

Q2. Which measure of central tendency is least affected by extreme values?

  • Mean
  • Median
  • Mode
  • Range

Correct Answer: Median

Q3. Variance is best defined as which of the following?

  • The average of the absolute deviations from the mean
  • The average of squared deviations from the mean
  • The square root of the standard deviation
  • The difference between maximum and minimum

Correct Answer: The average of squared deviations from the mean

Q4. Standard deviation describes which property of a dataset?

  • The central value of the data
  • The spread of data around the mean
  • The skewness of distribution
  • The number of observations

Correct Answer: The spread of data around the mean

Q5. Blood concentration measured on a scale with a true zero is an example of which data scale?

  • Nominal
  • Ordinal
  • Interval
  • Ratio

Correct Answer: Ratio

Q6. A normal distribution is characterized by which property?

  • Skewed to the right
  • Mean, median and mode are equal
  • Only positive values
  • All values are whole numbers

Correct Answer: Mean, median and mode are equal

Q7. A p-value represents which of the following?

  • The probability that the null hypothesis is true
  • The probability of observing the data or more extreme results if the null hypothesis is true
  • The effect size of an intervention
  • The clinical significance of a result

Correct Answer: The probability of observing the data or more extreme results if the null hypothesis is true

Q8. A Type I error occurs when you do what?

  • Fail to reject a false null hypothesis
  • Reject a true null hypothesis
  • Use the wrong statistical test
  • Confound two variables

Correct Answer: Reject a true null hypothesis

Q9. A 95% confidence interval for a mean implies which interpretation?

  • There is a 95% probability that the sample mean lies in this interval
  • 95% of individual observations fall within this interval
  • If the study were repeated many times, 95% of such intervals would contain the true population mean
  • The result is clinically significant

Correct Answer: If the study were repeated many times, 95% of such intervals would contain the true population mean

Q10. Which test is most appropriate to compare the means of two independent normally distributed samples?

  • Chi-square test
  • Independent (unpaired) t-test
  • Paired t-test
  • Mann–Whitney U test

Correct Answer: Independent (unpaired) t-test

Q11. The chi-square test is typically used to analyze which type of data?

  • Continuous normally distributed data
  • Categorical data in contingency tables
  • Time-to-event data
  • Paired measurements

Correct Answer: Categorical data in contingency tables

Q12. ANOVA (analysis of variance) is used primarily to:

  • Compare proportions between two groups
  • Compare means among three or more groups
  • Measure correlation between two variables
  • Estimate sample size

Correct Answer: Compare means among three or more groups

Q13. Pearson correlation coefficient measures which relationship?

  • Monotonic relationship between two ordinal variables
  • Linear relationship between two continuous variables
  • Causal relationship between two categorical variables
  • Differences between group means

Correct Answer: Linear relationship between two continuous variables

Q14. In regression analysis, the primary goal is to:

  • Test for differences in medians
  • Predict or explain a dependent variable using independent variables
  • Estimate prevalence
  • Calculate diagnostic accuracy

Correct Answer: Predict or explain a dependent variable using independent variables

Q15. Sensitivity of a diagnostic test is defined as:

  • The proportion of true negatives correctly identified
  • The proportion of true positives correctly identified
  • The overall accuracy of the test
  • The area under the ROC curve

Correct Answer: The proportion of true positives correctly identified

Q16. Specificity of a diagnostic test refers to:

  • The proportion of true negatives correctly identified
  • The proportion of true positives correctly identified
  • The prevalence of disease in the sample
  • The predictive value of a positive test

Correct Answer: The proportion of true negatives correctly identified

Q17. Positive predictive value (PPV) of a test is most affected by:

  • Test specificity only
  • Sample size only
  • Disease prevalence in the tested population
  • The number of negative results

Correct Answer: Disease prevalence in the tested population

Q18. Incidence differs from prevalence because incidence measures:

  • The total number of existing cases at a point in time
  • The proportion of false positives
  • The number of new cases occurring over a specified period
  • The sensitivity of a diagnostic test

Correct Answer: The number of new cases occurring over a specified period

Q19. The main purpose of randomization in clinical trials is to:

  • Increase sample size
  • Ensure identical treatment effects in all subjects
  • Reduce selection bias and balance confounders between groups
  • Eliminate the need for blinding

Correct Answer: Reduce selection bias and balance confounders between groups

Q20. Blinding in a clinical trial primarily helps to:

  • Decrease the sample size requirement
  • Prevent measurement and performance bias
  • Guarantee statistically significant results
  • Change the intervention effect

Correct Answer: Prevent measurement and performance bias

Q21. A Type II error (beta) refers to which situation?

  • Rejecting a true null hypothesis
  • Failing to reject a false null hypothesis
  • Using an incorrect p-value
  • Incorrect randomization

Correct Answer: Failing to reject a false null hypothesis

Q22. Statistical power is defined as:

  • The probability of a Type I error
  • The probability of detecting a true effect (1 − beta)
  • The p-value threshold for significance
  • The sample variance divided by the mean

Correct Answer: The probability of detecting a true effect (1 − beta)

Q23. Kaplan–Meier analysis is used to:

  • Compare proportions in two groups
  • Estimate survival function from time-to-event data
  • Calculate correlation coefficients
  • Adjust for confounders in logistic regression

Correct Answer: Estimate survival function from time-to-event data

Q24. The log-rank test is commonly used to:

  • Test the difference between two survival curves
  • Compare means across multiple groups
  • Assess diagnostic test sensitivity
  • Calculate sample size for a trial

Correct Answer: Test the difference between two survival curves

Q25. Which non-parametric test compares two independent samples when normality is not assumed?

  • Independent t-test
  • Mann–Whitney U test
  • Paired t-test
  • One-way ANOVA

Correct Answer: Mann–Whitney U test

Q26. Which test is appropriate to compare means of the same subjects before and after an intervention?

  • Independent (unpaired) t-test
  • Paired t-test
  • Chi-square test
  • Spearman correlation

Correct Answer: Paired t-test

Q27. Standard error (SE) of the mean is calculated as:

  • SD × n
  • SD / sqrt(n)
  • Variance × sqrt(n)
  • SD squared

Correct Answer: SD / sqrt(n)

Q28. For an unbiased estimate of population variance from a sample, degrees of freedom used is:

  • n
  • n + 1
  • n − 1
  • n/2

Correct Answer: n − 1

Q29. The Bonferroni correction is applied to:

  • Increase statistical power when multiple tests are performed
  • Control the family-wise error rate by adjusting alpha for multiple comparisons
  • Standardize data before analysis
  • Replace missing values

Correct Answer: Control the family-wise error rate by adjusting alpha for multiple comparisons

Q30. An ROC curve plots which pair of metrics, and what does AUC represent?

  • Sensitivity vs specificity; AUC is the p-value
  • Sensitivity vs 1−specificity; AUC measures overall diagnostic accuracy
  • Positive predictive value vs negative predictive value; AUC is prevalence
  • True negatives vs false negatives; AUC is the test cut-off

Correct Answer: Sensitivity vs 1−specificity; AUC measures overall diagnostic accuracy

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