Statistics and Data Analysis Quiz

Grade 10 · Math · Quiz

Test your understanding of data analysis, measures of center and spread, and data displays.

Questions

1. Find the median of: 2, 5, 7, 8, 12

   1. 5
   2. 6.8
   3. 7
   4. 8
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   Answer: 7

   Data is already sorted: 2,5,7,8,12. The middle value (3rd of 5) is 7.

2. The range of {4, 7, 2, 9, 1} is ___.

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   Answer: 8

   Range = max - min = 9 - 1 = 8.

3. A box plot displays the five-number summary of a data set.

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   Answer: True

   A box plot shows minimum, Q1, median, Q3, and maximum — the five-number summary.

4. In a data set, an outlier is a value that is:

   1. Equal to the mean
   2. Far from the other values
   3. The same as the median
   4. Less than the mode
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   Answer: Far from the other values

   An outlier is a data point unusually far from the rest of the data. Formally: below Q1-1.5·IQR or above Q3+1.5·IQR.

5. A correlation coefficient of r = 0.05 indicates:

   1. Strong positive correlation
   2. Strong negative correlation
   3. Little to no linear correlation
   4. Perfect correlation
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   Answer: Little to no linear correlation

   r = 0.05 is very close to 0, indicating essentially no linear relationship between the variables.

6. The measure of spread that is resistant to outliers is the ___.

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   Answer: IQR

   IQR = Q3 - Q1 measures the middle 50% spread and is not affected by extreme outliers. Range and standard deviation are both sensitive to outliers.

7. In a symmetric, bell-shaped distribution, the mean and median are approximately equal.

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   Answer: True

   In a symmetric distribution (like a normal bell curve), mean = median = mode. Skewness pulls the mean away from the median.

8. Which measure of center best describes data with extreme outliers?

   1. Mean
   2. Mode
   3. Median
   4. Range
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   Answer: Median

   The median is resistant to outliers. An extreme value changes the mean drastically but only slightly shifts the median.

9. On a scatterplot, points that trend downward from left to right show:

   1. Positive correlation
   2. Negative correlation
   3. No correlation
   4. Perfect correlation
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   Answer: Negative correlation

   A downward trend (as x increases, y decreases) indicates negative correlation. r would be negative.

10. Q1 is the ___ percentile of a data set.

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    Answer: 25th

    Q1 is the first quartile — the value at the 25th percentile, with 25% of data below it.

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