Quiz Chapter 7: Measures of Dispersion for Grouped Data

1. When constructing a frequency polygon directly from a histogram, line segments connect:

1. A. Midpoints of the top of adjacent bars
2. B. Upper boundaries of adjacent bars
3. C. Lower boundaries of adjacent bars
4. D. Top-left corners of adjacent bars

2. In an ogive, what variable is plotted on the horizontal axis (x-axis)?

1. A. Upper boundaries
2. B. Midpoints
3. C. Lower boundaries
4. D. Frequencies

3. For N = 200, the first quartile Q₁ occurs at a cumulative frequency of:

1. C. 50
2. A. 25
3. B. 100
4. D. 150

4. For the class interval 20 - 29, what is its lower boundary if the preceding class interval is 10 - 19?

1. A. 19.5
2. B. 20.0
3. C. 19.0
4. D. 24.5

5. Given ∑fx = 450 and ∑f = 30, calculate the mean x̄ of the grouped data.

1. A. 15
2. B. 12
3. C. 18
4. D. 20

6. Which graph MUST start at zero on the y-axis at the lower boundary of the first class interval?

1. A. Ogive
2. B. Histogram
3. C. Scatter plot
4. D. Bar chart

7. Given ∑f = 50, ∑fx = 300, and ∑fx² = 2300, calculate the mean x̄.

1. A. 6
2. B. 46
3. C. 60
4. D. 10

8. What is the standard deviation σ for a dataset with a variance of 16?

1. A. 4
2. B. 256
3. C. 8
4. D. 2

9. The interquartile range of a grouped dataset is defined as:

1. A. Q₃ - Q₁
2. B. Q₃ - Q₂
3. C. Q₂ - Q₁
4. D. Max value - Min value

10. Calculate the class size for the class interval 15 - 19.

1. A. 5
2. B. 4
3. C. 4.5
4. D. 17