5.3 - Measures of Dispersion.


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5.3.1 - Range.


1. What is the range of a dataset?
  • (A) The difference between the largest and smallest values
  • (B) The average of all values
  • (C) The midpoint of the dataset
  • (D) The most frequently occurring value
Correct Answer: (A) The difference between the largest and smallest values
2. Which of the following formulas represents how to calculate the range?
  • (A) Range = Maximum value - Minimum value
  • (B) Range = Mean - Mode
  • (C) Range = Median - Mode
  • (D) Range = Maximum value + Minimum value
Correct Answer: (A) Range = Maximum value - Minimum value
3. In a dataset of {3, 7, 5, 10, 2}, what is the range?
  • (A) 5
  • (B) 8
  • (C) 7
  • (D) 10
Correct Answer: (B) 8
4. Which of the following statements is true regarding the range?
  • (A) It provides information about the central tendency of the data.
  • (B) It is sensitive to outliers.
  • (C) It can be negative.
  • (D) It is a measure of the average distance of values from the mean.
Correct Answer: (B) It is sensitive to outliers.
5. When calculating the range of a dataset, what happens if the smallest and largest values are the same?
  • (A) The range is zero.
  • (B) The range is one.
  • (C) The range is infinite.
  • (D) The range is undefined.
Correct Answer: (A) The range is zero.
6. Which of the following datasets has the largest range?
  • (A) {1, 2, 3, 4, 5}
  • (B) {10, 15, 20, 25, 30}
  • (C) {5, 10, 15, 20, 100}
  • (D) {8, 12, 16, 20}
Correct Answer: (C) {5, 10, 15, 20, 100}
7. Why is the range considered a limited measure of dispersion?
  • (A) It considers all data points.
  • (B) It ignores the distribution of values.
  • (C) It is always positive.
  • (D) It is easy to calculate.
Correct Answer: (B) It ignores the distribution of values.
8. If the range of a dataset is 20 and the minimum value is 15, what is the maximum value?
  • (A) 35
  • (B) 25
  • (C) 20
  • (D) 30
Correct Answer: (A) 35
9. In which situation would the range be a less informative measure of dispersion?
  • (A) When the dataset has outliers
  • (B) When the data is normally distributed
  • (C) When the data has a large sample size
  • (D) When all values are unique
Correct Answer: (A) When the dataset has outliers
10. Which of the following datasets has a range of 0?
  • (A) {2, 2, 2, 2, 2}
  • (B) {1, 2, 3, 4, 5}
  • (C) {5, 10, 15, 20}
  • (D) {7, 8, 9, 10, 11}
Correct Answer: (A) {2, 2, 2, 2, 2}

5.3.2 - Quartile Deviation.


11. What is quartile deviation?
  • (A) The difference between the maximum and minimum values
  • (B) Half the difference between the first quartile (Q1) and the third quartile (Q3)
  • (C) The average of the dataset
  • (D) The median of the dataset
Correct Answer: (B) Half the difference between the first quartile (Q1) and the third quartile (Q3)
12. How is the quartile deviation calculated?
  • (A) QD = Q3 - Q1
  • (B) QD = (Q3 - Q1) / 2
  • (C) QD = Q1 + Q3
  • (D) QD = (Q1 + Q3) / 2
Correct Answer: (B) QD = (Q3 - Q1) / 2
13. If the first quartile (Q1) is 10 and the third quartile (Q3) is 20, what is the quartile deviation?
  • (A) 5
  • (B) 10
  • (C) 15
  • (D) 20
Correct Answer: (A) 5
14. Which of the following statements about quartile deviation is true?
  • (A) It is affected by extreme values.
  • (B) It provides a measure of the central tendency of the data.
  • (C) It is a measure of variability.
  • (D) It cannot be calculated for grouped data.
Correct Answer: (C) It is a measure of variability.
15. When is the quartile deviation considered a useful measure of dispersion?
  • (A) When the data has a normal distribution
  • (B) When the data contains outliers
  • (C) When the data is skewed
  • (D) When there are few data points
Correct Answer: (C) When the data is skewed
16. What does a small quartile deviation indicate about a dataset?
  • (A) The values are widely spread apart.
  • (B) The values are closely clustered around the median.
  • (C) There are significant outliers in the data.
  • (D) The dataset is uniform.
Correct Answer: (B) The values are closely clustered around the median.
17. Which of the following is NOT a characteristic of quartile deviation?
  • (A) It is always a positive value.
  • (B) It can be calculated using both ungrouped and grouped data.
  • (C) It is sensitive to extreme values.
  • (D) It is a measure of the spread of the middle 50% of the data.
Correct Answer: (C) It is sensitive to extreme values.
18. If a dataset has a quartile deviation of 0, what does this imply?
  • (A) The data has high variability.
  • (B) All values in the dataset are identical.
  • (C) The dataset is normally distributed.
  • (D) The dataset contains outliers.
Correct Answer: (B) All values in the dataset are identical.
19. In a dataset, if Q1 = 15 and Q3 = 30, what is the interquartile range (IQR)?
  • (A) 10
  • (B) 15
  • (C) 30
  • (D) 45
Correct Answer: (B) 15
20. How does quartile deviation relate to interquartile range (IQR)?
  • (A) Quartile deviation is the same as IQR.
  • (B) Quartile deviation is half of the IQR.
  • (C) Quartile deviation is twice the IQR.
  • (D) Quartile deviation and IQR are unrelated.
Correct Answer: (B) Quartile deviation is half of the IQR.

5.3.3 - Mean Deviation.


21. What is mean deviation?
  • (A) The average of all values in a dataset
  • (B) The average of the absolute differences between each data point and the mean
  • (C) The difference between the maximum and minimum values
  • (D) The median of the dataset
Correct Answer: (B) The average of the absolute differences between each data point and the mean
22. How is mean deviation calculated?
  • (A) MD = Σ|x - mean| / n
  • (B) MD = Σ(x - mean) / n
  • (C) MD = Σ|x - median| / n
  • (D) MD = Σ(x - mode) / n
Correct Answer: (A) MD = Σ|x - mean| / n
23. If the dataset is {5, 10, 15}, what is the mean deviation?
  • (A) 5
  • (B) 10
  • (C) 15
  • (D) 0
Correct Answer: (A) 5
24. Which of the following statements about mean deviation is true?
  • (A) It is affected by outliers.
  • (B) It can be negative.
  • (C) It is a measure of central tendency.
  • (D) It considers all data points in the calculation.
Correct Answer: (D) It considers all data points in the calculation.
25. Why is mean deviation considered a useful measure of dispersion?
  • (A) It is easy to compute.
  • (B) It provides a precise measure of central tendency.
  • (C) It is robust to outliers.
  • (D) It focuses only on extreme values.
Correct Answer: (A) It is easy to compute.
26. How does mean deviation differ from standard deviation?
  • (A) Mean deviation is always greater than standard deviation.
  • (B) Mean deviation uses absolute values, while standard deviation uses squared values.
  • (C) Mean deviation cannot be used for grouped data.
  • (D) Mean deviation considers only the largest and smallest values.
Correct Answer: (B) Mean deviation uses absolute values, while standard deviation uses squared values.
27. If the mean of a dataset is 50 and the absolute deviations from the mean are {5, 10, 15}, what is the mean deviation?
  • (A) 10
  • (B) 15
  • (C) 5
  • (D) 20
Correct Answer: (A) 10
28. In which situation is mean deviation preferred over standard deviation?
  • (A) When dealing with small datasets
  • (B) When data contains outliers
  • (C) When data is normally distributed
  • (D) When calculating probabilities
Correct Answer: (B) When data contains outliers
29. If the mean deviation of a dataset is 0, what does this imply?
  • (A) All values in the dataset are the same.
  • (B) The dataset has high variability.
  • (C) There are extreme outliers present.
  • (D) The dataset is normally distributed.
Correct Answer: (A) All values in the dataset are the same.
30. Which of the following datasets will likely yield the highest mean deviation?
  • (A) {10, 10, 10, 10}
  • (B) {1, 2, 3, 4}
  • (C) {0, 50, 100}
  • (D) {20, 20, 20, 20}
Correct Answer: (C) {0, 50, 100}
31. When calculating the mean deviation, what should be done with the absolute differences?
  • (A) They should be squared.
  • (B) They should be summed and divided by the number of observations.
  • (C) They should be ignored.
  • (D) They should be multiplied by the mean.
Correct Answer: (B) They should be summed and divided by the number of observations.
32. How does mean deviation provide insights about a dataset?
  • (A) It identifies the most common value.
  • (B) It indicates how closely the data points cluster around the mean.
  • (C) It reveals the shape of the distribution.
  • (D) It determines the largest value in the dataset.
Correct Answer: (B) It indicates how closely the data points cluster around the mean.
33. If a dataset has high variability, what can be inferred about its mean deviation?
  • (A) It will be low.
  • (B) It will be high.
  • (C) It cannot be determined.
  • (D) It will always be zero.
Correct Answer: (B) It will be high.
34. Mean deviation is most suitable for which type of data?
  • (A) Categorical data
  • (B) Ordinal data
  • (C) Continuous data
  • (D) Qualitative data
Correct Answer: (C) Continuous data.
35. If a dataset consists of {4, 8, 12, 16}, what is the mean deviation?
  • (A) 2
  • (B) 3
  • (C) 4
  • (D) 5
Correct Answer: (B) 3

5.3.4 - Standard Deviation and Variance.


36. What is standard deviation?
  • (A) The average of the dataset
  • (B) A measure of the spread of data points around the mean
  • (C) The difference between the maximum and minimum values
  • (D) The median of the dataset
Correct Answer: (B) A measure of the spread of data points around the mean
37. How is variance defined?
  • (A) The average of absolute deviations from the mean
  • (B) The average of the squared deviations from the mean
  • (C) The difference between the highest and lowest values
  • (D) The sum of all data points divided by the number of points
Correct Answer: (B) The average of the squared deviations from the mean
38. The formula for variance (σ²) in a population is:
  • (A) σ² = Σ(x - μ)² / N
  • (B) σ² = Σ(x - x̄)² / n
  • (C) σ² = Σ|x - μ| / N
  • (D) σ² = Σ(x - x̄) / n
Correct Answer: (A) σ² = Σ(x - μ)² / N
39. The relationship between variance and standard deviation is:
  • (A) Standard deviation is the square of the variance.
  • (B) Variance is the square of the standard deviation.
  • (C) They are always equal.
  • (D) They are unrelated.
Correct Answer: (B) Variance is the square of the standard deviation.
40. If the standard deviation of a dataset is 0, what does this imply?
  • (A) The data points are widely spread apart.
  • (B) The data has high variability.
  • (C) All data points are identical.
  • (D) There are significant outliers in the data.
Correct Answer: (C) All data points are identical.
41. How do you calculate the sample variance (s²)?
  • (A) s² = Σ(x - x̄)² / n
  • (B) s² = Σ(x - x̄)² / (n - 1)
  • (C) s² = Σ|x - x̄| / n
  • (D) s² = Σ(x - μ)² / N
Correct Answer: (B) s² = Σ(x - x̄)² / (n - 1)
42. Which of the following is a characteristic of standard deviation?
  • (A) It cannot be negative.
  • (B) It can be negative.
  • (C) It is always greater than the mean.
  • (D) It ignores outliers.
Correct Answer: (A) It cannot be negative.
43. When would you use variance instead of standard deviation?
  • (A) When you want a measure that is easier to interpret
  • (B) When dealing with large datasets
  • (C) When performing statistical analysis that requires squared values
  • (D) When the dataset contains outliers
Correct Answer: (C) When performing statistical analysis that requires squared values
44. If a dataset has a mean of 10 and the data points are {6, 8, 12, 14}, what is the standard deviation?
  • (A) 2
  • (B) 4
  • (C) 3
  • (D) 5
Correct Answer: (C) 3
45. How does increasing the spread of a dataset affect the standard deviation?
  • (A) It decreases the standard deviation.
  • (B) It has no effect on the standard deviation.
  • (C) It increases the standard deviation.
  • (D) It changes the mean.
Correct Answer: (C) It increases the standard deviation.
46. If a dataset has a high variance, what does it imply about the data?
  • (A) The data points are clustered closely around the mean.
  • (B) The data points are widely spread out from the mean.
  • (C) The data is uniform.
  • (D) The data has no variability.
Correct Answer: (B) The data points are widely spread out from the mean.
47. Which of the following statements is true regarding variance?
  • (A) It is always expressed in the same units as the data.
  • (B) It can be expressed in squared units of the data.
  • (C) It cannot be calculated for grouped data.
  • (D) It is less useful than mean deviation.
Correct Answer: (B) It can be expressed in squared units of the data.
48. What is the effect of outliers on standard deviation?
  • (A) It has no effect.
  • (B) It decreases the standard deviation.
  • (C) It can significantly increase the standard deviation.
  • (D) It is not affected by outliers.
Correct Answer: (C) It can significantly increase the standard deviation.
49. Which of the following data sets has the highest variance?
  • (A) {2, 2, 2, 2}
  • (B) {1, 2, 3, 4}
  • (C) {10, 20, 30, 40}
  • (D) {5, 5, 5, 5}
Correct Answer: (C) {10, 20, 30, 40}
50. When calculating the standard deviation, what is the first step?
  • (A) Calculate the mean.
  • (B) Find the median.
  • (C) Identify the maximum value.
  • (D) Determine the mode.
Correct Answer: (A) Calculate the mean.

5.3.5- Coefficient of Variation.


51. What does the coefficient of variation (CV) measure?
  • (A) The central tendency of a dataset
  • (B) The relative variability of a dataset
  • (C) The maximum value in a dataset
  • (D) The average value of a dataset
Correct Answer: (B) The relative variability of a dataset
52. The coefficient of variation is calculated as:
  • (A) CV = (Standard Deviation / Mean) × 100
  • (B) CV = (Mean / Standard Deviation) × 100
  • (C) CV = (Variance / Mean) × 100
  • (D) CV = (Mean / Variance) × 100
Correct Answer: (A) CV = (Standard Deviation / Mean) × 100
53. A higher coefficient of variation indicates:
  • (A) Less relative variability
  • (B) More relative variability
  • (C) No variability
  • (D) The same variability as other datasets
Correct Answer: (B) More relative variability
54. When is the coefficient of variation particularly useful?
  • (A) When comparing datasets with different units
  • (B) When datasets are small
  • (C) When measuring only central tendency
  • (D) When calculating mean deviation
Correct Answer: (A) When comparing datasets with different units
55. If the mean of a dataset is zero, what happens to the coefficient of variation?
  • (A) It is zero.
  • (B) It is undefined.
  • (C) It is infinite.
  • (D) It is always positive.
Correct Answer: (B) It is undefined.
56. The coefficient of variation is expressed as:
  • (A) A fraction
  • (B) A percentage
  • (C) A decimal
  • (D) An integer
Correct Answer: (B) A percentage
57. Which of the following statements is true regarding the coefficient of variation?
  • (A) It can be negative.
  • (B) It is a measure of dispersion that is independent of the units of measurement.
  • (C) It is only applicable to normally distributed data.
  • (D) It is calculated using the median.
Correct Answer: (B) It is a measure of dispersion that is independent of the units of measurement.
58. If Dataset A has a mean of 50 and a standard deviation of 10, and Dataset B has a mean of 100 and a standard deviation of 20, which dataset has a higher coefficient of variation?
  • (A) Dataset A
  • (B) Dataset B
  • (C) Both have the same CV
  • (D) Cannot be determined without additional information
Correct Answer: (A) Dataset A
59. The coefficient of variation is particularly useful in which field?
  • (A) Pure mathematics
  • (B) Financial analysis
  • (C) Geography
  • (D) Historical research
Correct Answer: (B) Financial analysis
60. What does a CV of 0% indicate about a dataset?
  • (A) The dataset has high variability.
  • (B) The dataset has low variability.
  • (C) All data points are identical.
  • (D) The dataset has negative values.
Correct Answer: (C) All data points are identical.
61. If the coefficient of variation for a dataset is lower than 20%, what can be inferred?
  • (A) The dataset has very high variability.
  • (B) The dataset has very low variability.
  • (C) The dataset is normally distributed.
  • (D) The mean is greater than the standard deviation.
Correct Answer: (B) The dataset has very low variability.
62. If the mean of a dataset is increased while the standard deviation remains constant, what happens to the coefficient of variation?
  • (A) It increases.
  • (B) It decreases.
  • (C) It remains the same.
  • (D) It becomes undefined.
Correct Answer: (B) It decreases.
63. In which scenario is the coefficient of variation not useful?
  • (A) When comparing two different datasets with the same units
  • (B) When analyzing datasets with different units
  • (C) When the mean of the dataset is zero
  • (D) When dealing with normally distributed data
Correct Answer: (C) When the mean of the dataset is zero.
64. The coefficient of variation is particularly useful when:
  • (A) Data is normally distributed
  • (B) Comparing the relative variability of two or more datasets
  • (C) The data points are all identical
  • (D) The mean and median are the same
Correct Answer: (B) Comparing the relative variability of two or more datasets.
65. What is the coefficient of variation for a dataset with a standard deviation of 15 and a mean of 75?
  • (A) 10%
  • (B) 20%
  • (C) 25%
  • (D) 30%
Correct Answer: (B) 20%