1. In biomedical research, data are primarily collected to:
A. Increase sample size
B. Generate meaningful information
C. Reduce bias
D. Test laboratory equipment
Answer: B
2. Data become useful when they are:
A. Stored in a computer
B. Summarized and interpreted into information
C. Collected from hospitals only
D. Presented in tables only
Answer: B
3. Data in biomedical research are broadly classified into:
A. Primary and secondary
B. Qualitative and Quantitative
C. Experimental and observational
D. Cross-sectional and longitudinal
Answer: B
4. Which of the following is an example of qualitative data?
A. Height
B. Weight
C. Eye color
D. Blood glucose level
Answer: C
5. Qualitative data can be further classified into:
A. Discrete and Continuous
B. Nominal and Ordinal
C. Ratio and Interval
D. Primary and Secondary
Answer: B
6. Which of the following is an example of nominal data?
A. Stages of cancer
B. Pain severity
C. Blood group
D. Body weight
Answer: C
7. Which characteristic best describes nominal data?
A. Values have a natural order.
B. Values represent measurable quantities.
C. Categories have no inherent order.
D. Values are always continuous.
Answer: C
8. Which of the following is an example of ordinal data?
A. Height
B. Number of children
C. Stages of disease
D. Serum cholesterol
Answer: C
9. Ordinal data differ from nominal data because ordinal data:
A. Can be measured precisely.
B. Have categories arranged in a meaningful order.
C. Are always numerical.
D. Have equal intervals between categories.
Answer: B
10. Quantitative data are broadly classified into:
A. Nominal and Ordinal
B. Discrete and Continuous
C. Primary and Secondary
D. Cross-sectional and Cohort
Answer: B
11. Which of the following is an example of discrete quantitative data?
A. Height
B. Weight
C. Number of siblings
D. Blood pressure
Answer: C
12. Discrete data are characterized by:
A. Fractional values only
B. Whole-number counts
C. Ordered categories
D. Non-measurable characteristics
Answer: B
13. Which of the following is an example of continuous data?
A. Family size
B. Number of admissions
C. Height
D. Number of pregnancies
Answer: C
14. Continuous data are best described as:
A. Data measured on a continuous scale
B. Categories without order
C. Whole numbers only
D. Binary variables only
Answer: A
15. Which of the following is a continuous variable?
A. Weight
B. Blood group
C. Gender
D. Marital status
Answer: A
16. Different types of data require:
A. The same statistical analysis
B. Different analytical methods
C. No statistical analysis
D. Only descriptive statistics
Answer: B
17. Why is summarization of data important?
A. To increase sample size
B. To convert raw data into useful information
C. To eliminate bias
D. To improve randomization
Answer: B
18. Which of the following is considered a measure of central tendency?
A. Range
B. Variance
C. Mean
D. Standard deviation
Answer: C
19. The arithmetic mean is calculated by:
A. Dividing the largest value by the smallest value
B. Adding all observations and dividing by the total number of observations
C. Identifying the middle observation
D. Identifying the most frequent observation
Answer: B
20. The mathematical notation for the sum of observations is:
A. μ
B. x̄
C. ΣXi
D. SD
Answer: C
21. The sample mean is represented by:
A. μ
B. x̄
C. σ
D. CV
Answer: B
22. The population mean is represented by:
A. x̄
B. Σ
C. μ
D. SD
Answer: C
23. Which measure of central tendency is most commonly used?
A. Mode
B. Median
C. Arithmetic Mean
D. Geometric Mean
Answer: C
24. The arithmetic mean is most appropriate when:
A. Data contain extreme outliers.
B. All observations are considered and no major extreme values distort the data.
C. Variables are nominal.
D. Data consist only of ranks.
Answer: B
25. Which statement BEST summarizes the measures of central tendency?
A. Measures of central tendency describe the central or typical value of a dataset. The arithmetic mean is calculated using all observations and is suitable for normally distributed quantitative data. The median is the middle value and is preferred for skewed data or datasets with extreme values, while the mode represents the most frequently occurring value and is especially useful for categorical (nominal) data.
B. Measures of central tendency are used only for qualitative variables, and the arithmetic mean is the best measure regardless of data distribution.
C. The mean, median, and mode always produce identical results and can be used interchangeably for all types of data.
D. The mode is the most accurate measure for every dataset because it is unaffected by sample size and data distribution.
Answer: A
26. Which measure of central tendency is least affected by extreme values?
A. Mean
B. Median
C. Mode
D. Range
Answer: B
27. The median is defined as the:
A. Average of all observations
B. Most frequently occurring value
C. Middle value of an ordered dataset
D. Difference between the maximum and minimum values
Answer: C
28. The median divides a dataset into:
A. Three equal parts
B. Four equal parts
C. Two equal halves
D. Five equal groups
Answer: C
29. In an ordered dataset containing 11 observations, the median is located at:
A. 5th observation
B. 6th observation
C. 7th observation
D. 8th observation
Answer: B
30. For an even number of observations, the median is calculated as:
A. The first value
B. The last value
C. The average of the two middle values
D. The most frequent value
Answer: C
31. Which measure of central tendency is preferred when the dataset contains extreme outliers?
A. Mean
B. Median
C. Variance
D. Standard deviation
Answer: B
32. Why is the arithmetic mean sensitive to extreme values?
A. It considers only the middle observation.
B. It uses all observations in the dataset.
C. It ignores large values.
D. It is calculated using ranks only.
Answer: B
33. In the lecture example, the duration of hospital stay included one patient admitted for 77 days. Which measure best represented the average hospital stay?
A. Mean
B. Median
C. Mode
D. Range
Answer: B
34. In the hospital stay example, the mean was higher than the median because:
A. The sample size was too small.
B. The data contained an extreme value.
C. The data were qualitative.
D. The observations were unordered.
Answer: B
35. Which measure of central tendency is defined as the value occurring most frequently?
A. Mean
B. Median
C. Mode
D. Variance
Answer: C
36. The mode is especially useful for:
A. Continuous variables only
B. Nominal data
C. Ratio data only
D. Interval data only
Answer: B
37. Which measure of central tendency can be used for nominal variables?
A. Mean
B. Median
C. Mode
D. Standard deviation
Answer: C
38. Which statement regarding the mode is TRUE?
A. Every dataset has exactly one mode.
B. A dataset may have more than one mode.
C. Mode cannot be used for qualitative variables.
D. Mode is always equal to the median.
Answer: B
39. A dataset in which every value occurs with equal frequency has:
A. One mode
B. Two modes
C. No mode
D. Infinite modes
Answer: C
40. In epidemiology, the mode is commonly used in:
A. Regression analysis
B. Epidemic curves
C. Clinical trials
D. Cohort studies
Answer: B
41. In an epidemic curve, the modal class provides an estimate of:
A. Disease prevalence
B. Relative risk
C. Incubation period
D. Odds ratio
Answer: C
42. Which statement best compares the three measures of central tendency?
A. Mean ignores all observations.
B. Median is affected most by outliers.
C. Mode identifies the most frequent value.
D. Mean is suitable only for qualitative variables.
Answer: C
43. Measures such as mean, median, and mode are collectively known as:
A. Measures of association
B. Measures of central tendency
C. Measures of variability
D. Measures of risk
Answer: B
44. Besides knowing the average, researchers should also understand:
A. Sample identification numbers
B. Variability or dispersion of the data
C. Publication year
D. Study funding
Answer: B
45. Which example was used in the lecture to explain the importance of variability?
A. Height of school children
B. Swimming pool depth
C. Blood pressure measurements
D. Birth weight distribution
Answer: B
46. The range is defined as:
A. Mean divided by standard deviation
B. Maximum value minus minimum value
C. Q3 minus Q1
D. Average deviation from the mean
Answer: B
47. The greatest advantage of the range is that it is:
A. Unaffected by extreme values
B. Easy and quick to calculate
C. Based on all observations
D. Suitable for regression analysis
Answer: B
48. Which is a major limitation of the range?
A. It cannot be calculated.
B. It uses only the smallest and largest observations.
C. It is based on every observation equally.
D. It ignores extreme values.
Answer: B
49. The range is highly influenced by:
A. Randomization
B. Extreme values
C. Sample size only
D. Matching
Answer: B
50. Which statement BEST summarizes the median, mode, and range?
A. The median is the middle value of an ordered dataset and is preferred when extreme values are present. The mode is the most frequently occurring value and is particularly useful for nominal variables and epidemic curves. The range is the difference between the maximum and minimum values and provides a simple measure of variability, although it is highly influenced by extreme observations.
B. The median is always the average of all observations, the mode can only be calculated for quantitative variables, and the range is unaffected by outliers.
C. Mean, median, mode, and range are identical measures that provide the same information about a dataset regardless of data type or distribution.
D. The range is the most reliable measure of central tendency because it represents the average value of all observations and is unaffected by extreme values.
Answer: A
51. Which measure of dispersion is defined as the difference between the maximum and minimum values?
A. Variance
B. Standard Deviation
C. Range
D. Interquartile Range
Answer: C
52. The primary advantage of the Range is that it is:
A. Unaffected by extreme values
B. Based on all observations
C. Simple and quick to calculate
D. Suitable for skewed data
Answer: C
53. The major limitation of the Range is that it:
A. Uses only the smallest and largest observations
B. Cannot be calculated for quantitative data
C. Is always equal to the standard deviation
D. Is unaffected by outliers
Answer: A
54. Which measure of dispersion is least affected by extreme values?
A. Range
B. Variance
C. Interquartile Range
D. Mean Deviation
Answer: C
55. The Interquartile Range (IQR) is calculated as:
A. Q1 + Q3
B. Maximum − Minimum
C. Q3 − Q1
D. Mean ÷ Standard Deviation
Answer: C
56. The Interquartile Range represents:
A. All observations
B. Middle 50% of the observations
C. Upper 25% only
D. Lower 25% only
Answer: B
57. Which measure of variability removes the influence of most extreme values by ignoring the lowest and highest quarters of data?
A. Range
B. Mean
C. Interquartile Range
D. Mode
Answer: C
58. Which statement regarding the Interquartile Range is TRUE?
A. It includes every observation in the dataset.
B. It is unaffected by extreme values.
C. It is calculated using only the maximum value.
D. It is used only for nominal variables.
Answer: B
59. Which of the following is a limitation of the Interquartile Range?
A. It is influenced by every observation.
B. It considers only the middle 50% of the data.
C. It cannot be calculated from ordered data.
D. It is affected by every outlier.
Answer: B
60. Which measure is preferred for describing variability in highly skewed data?
A. Standard Deviation
B. Variance
C. Interquartile Range
D. Mean
Answer: C
61. Mean deviation is calculated by:
A. Finding the difference between maximum and minimum values
B. Calculating the average deviation of observations from the mean
C. Dividing the variance by the mean
D. Averaging the quartiles
Answer: B
62. Why is the simple average of deviations from the mean always zero?
A. Because the sample size is small
B. Positive and negative deviations cancel each other
C. The mean equals the median
D. The values are arranged in order
Answer: B
63. To overcome the cancellation of positive and negative deviations, mean deviation uses:
A. Squared values
B. Absolute values
C. Quartiles
D. Percentages
Answer: B
64. Which statement best describes Absolute Mean Deviation?
A. It ignores the sign of deviations from the mean.
B. It uses only extreme values.
C. It is identical to variance.
D. It is calculated only for nominal data.
Answer: A
65. A limitation of Absolute Mean Deviation is that it:
A. Cannot be calculated
B. Ignores the direction (sign) of deviations
C. Uses only two observations
D. Is affected only by median
Answer: B
66. Variance is calculated by:
A. Averaging the absolute deviations
B. Averaging the squared deviations from the mean
C. Dividing the maximum by the minimum
D. Finding the most frequent value
Answer: B
67. Why are deviations squared while calculating variance?
A. To reduce sample size
B. To eliminate negative signs
C. To calculate the median
D. To increase the mean
Answer: B
68. Standard Deviation (SD) is defined as:
A. Difference between Q3 and Q1
B. Square root of the variance
C. Maximum minus minimum value
D. Average of quartiles
Answer: B
69. The square of the Standard Deviation equals:
A. Mean
B. Variance
C. Range
D. Interquartile Range
Answer: B
70. Which measure of variability is expressed in the same units as the original observations?
A. Variance
B. Standard Deviation
C. Mean Deviation
D. Range
Answer: B
71. Why is Standard Deviation preferred over Variance?
A. It is expressed in the original measurement units.
B. It ignores all outliers.
C. It is used only for qualitative data.
D. It is easier than the mean.
Answer: A
72. Which measure of variability is most widely used in biomedical research?
A. Range
B. Mean Deviation
C. Standard Deviation
D. Interquartile Range
Answer: C
73. Standard Deviation is commonly reported together with:
A. Median
B. Mode
C. Arithmetic Mean
D. Quartiles
Answer: C
74. Which pair is generally preferred for describing normally distributed quantitative data?
A. Median and Interquartile Range
B. Mean and Standard Deviation
C. Mode and Range
D. Mode and Median
Answer: B
75. Which statement BEST summarizes the measures of dispersion?
A. Measures of dispersion describe the spread of observations around the central value. Range is simple but influenced by extreme values. Interquartile Range describes the middle 50% of observations and is resistant to outliers. Variance is the average of squared deviations from the mean, while Standard Deviation is the square root of the variance and is the most commonly used measure because it is expressed in the original units of measurement.
B. All measures of dispersion are unaffected by extreme values and provide identical information.
C. Standard Deviation is calculated by subtracting the minimum value from the maximum value.
D. Variance and Standard Deviation are measures of central tendency rather than variability.
Answer: A
76. A researcher is comparing the ages of 100 healthy adults with no extreme values. Which measures should be reported?
A. Median and Interquartile Range
B. Mean and Standard Deviation
C. Mode and Range
D. Median and Mode
Answer: B
77. A study on hospital stay includes a few patients admitted for several months, making the data highly skewed. Which summary statistics are most appropriate?
A. Mean and Standard Deviation
B. Mean and Range
C. Median and Interquartile Range
D. Mode and Variance
Answer: C
78. Which measure of variability is preferred when comparing datasets measured in different units?
A. Range
B. Variance
C. Coefficient of Variation
D. Interquartile Range
Answer: C
79. The Coefficient of Variation (CV) is calculated as:
A. Mean × Standard Deviation
B. Standard Deviation ÷ Mean × 100
C. Mean ÷ Variance × 100
D. Variance ÷ Mean × 100
Answer: B
80. Why is the Coefficient of Variation considered a unit-free measure?
A. It ignores variability.
B. The units of the mean and standard deviation cancel each other.
C. It is calculated only for percentages.
D. It uses quartiles instead of measurements.
Answer: B
81. Which statement regarding the Coefficient of Variation is TRUE?
A. It measures central tendency.
B. It expresses relative variability as a percentage.
C. It is identical to variance.
D. It is used only for qualitative variables.
Answer: B
82. Two laboratories measure glucose concentration using different instruments. Which statistic is most suitable for comparing the consistency of their measurements?
A. Median
B. Mode
C. Coefficient of Variation
D. Range
Answer: C
83. Which measure is expressed as a percentage?
A. Variance
B. Standard Deviation
C. Coefficient of Variation
D. Range
Answer: C
84. Which of the following is NOT a measure of central tendency?
A. Mean
B. Median
C. Mode
D. Standard Deviation
Answer: D
85. Which of the following is NOT a measure of dispersion?
A. Range
B. Variance
C. Standard Deviation
D. Mean
Answer: D
86. A researcher wishes to compare the variability of body weight and blood pressure measured in different units. Which measure should be used?
A. Range
B. Standard Deviation
C. Coefficient of Variation
D. Median
Answer: C
87. Which combination is generally recommended for quantitative data without extreme values?
A. Median and Interquartile Range
B. Mean and Standard Deviation
C. Mode and Range
D. Mean and Mode
Answer: B
88. Which combination is generally recommended for skewed data with outliers?
A. Mean and Standard Deviation
B. Median and Interquartile Range
C. Mean and Variance
D. Mode and Standard Deviation
Answer: B
89. Why is Standard Deviation preferred over Range for describing variability?
A. It uses all observations in the dataset.
B. It ignores most observations.
C. It depends only on the maximum value.
D. It is unaffected by sample size.
Answer: A
90. Which measure provides the best estimate of overall variability in normally distributed data?
A. Range
B. Interquartile Range
C. Standard Deviation
D. Mode
Answer: C
91. A dataset has a mean of 50 and a standard deviation of 5. What is the Coefficient of Variation?
A. 5%
B. 10%
C. 15%
D. 20%
Answer: B
92. A dataset has a mean of 80 and a standard deviation of 16. What is the Coefficient of Variation?
A. 10%
B. 15%
C. 20%
D. 25%
Answer: C
93. Which measure is most appropriate for comparing the precision of two laboratory methods?
A. Median
B. Coefficient of Variation
C. Mode
D. Range
Answer: B
94. Which of the following is the MOST commonly reported descriptive summary in biomedical research?
A. Mean ± Standard Deviation
B. Mode ± Range
C. Median ± Variance
D. Mean ± Range
Answer: A
95. A researcher reports only the mean without any measure of variability. What important information is missing?
A. Sample size
B. Dispersion of observations around the mean
C. Data type
D. Study design
Answer: B
96. Which statement is CORRECT regarding Standard Deviation?
A. It is always zero.
B. It is the square root of variance and is expressed in the original measurement units.
C. It measures central tendency.
D. It is calculated using only maximum and minimum values.
Answer: B
97. Which statement best explains why Median and Interquartile Range are often reported together?
A. Both are unaffected by extreme values and provide a robust summary for skewed data.
B. They are used only for nominal variables.
C. They replace all other descriptive statistics.
D. They are calculated only from continuous data.
Answer: A
98. Which of the following BEST describes the relationship between Variance and Standard Deviation?
A. Variance is the square root of Standard Deviation.
B. Standard Deviation is the square root of Variance.
C. Both are identical.
D. Neither measures variability.
Answer: B
99. A biostatistician is analyzing blood pressure values that are approximately normally distributed and contain no outliers. Which descriptive statistics should be reported?
A. Mean ± Standard Deviation
B. Median + Interquartile Range
C. Mode + Range
D. Median + Mode
Answer: A
100. Which statement BEST summarizes the Measurement of Study Variables?
A. Study variables may be qualitative (nominal or ordinal) or quantitative (discrete or continuous). Appropriate descriptive statistics depend on the type and distribution of data. Mean and Standard Deviation are preferred for quantitative data without extreme values, whereas Median and Interquartile Range are more appropriate for skewed data or data with outliers. Mode is useful for categorical variables, and the Coefficient of Variation compares relative variability between different datasets. Selecting thefindings. correct measure of central tendency and dispersion is essential for accurate interpretation of biomedical research
B. Mean and Standard Deviation should always be used regardless of data type or distribution.
C. Mode and Range are sufficient for all biomedical research data.
D. All variables require identical statistical methods and descriptive measures.
Answer: A
