Statistics and Data Analysis Quiz

Grade 9 · Math · Quiz

Test your knowledge of measures of center, spread, and data interpretation.

Questions

Find the median of: 3, 7, 8, 10, 15
1. 7
2. 8
3. 10
4. 9
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Answer: 8
Ordered: 3, 7, 8, 10, 15 — the middle value is 8.
A data set can have more than one mode.
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Answer: True
A bimodal data set has two modes; multimodal sets have more than two.
Find the mean of: 10, 20, 30, 40
1. 20
2. 25
3. 30
4. 35
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Answer: 25
Mean = (10 + 20 + 30 + 40)/4 = 100/4 = 25.
If Q1 = 10 and Q3 = 22, the IQR is ___.
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Answer: 12
IQR = Q3 − Q1 = 22 − 10 = 12.
The data set is {2, 3, 3, 4, 100}. Which measure best represents the center?
1. Mean
2. Median
3. Mode
4. Range
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Answer: Median
The value 100 is an outlier that would distort the mean; the median is resistant.
The range of a data set can be negative.
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Answer: False
Range = max − min; since max ≥ min, range is always ≥ 0.
Find the mode of: {5, 5, 7, 8, 9, 9, 9}
1. 5
2. 7
3. 9
4. 8
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Answer: 9
9 appears 3 times — more than any other value.
The difference between the maximum and minimum in a data set is called the ___.
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Answer: range
Range = maximum value − minimum value.
In a box plot, the line inside the box represents the:
1. Mean
2. Median
3. Mode
4. Range
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Answer: Median
In a box plot (box-and-whisker), the middle line inside the box marks the median.
Adding a very high outlier to a data set will most likely:
1. Increase the median significantly
2. Decrease the mean
3. Increase the mean
4. Have no effect on any measure
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Answer: Increase the mean
A high outlier raises the sum and therefore the mean, while the median barely moves.

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