AP Statistics · Topic 1.9

Comparing Distributions of a Quantitative Variable Practice

Part of Exploring One-Variable Data.(UNC-1.G)

Practice questions

9

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Sample questions

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  1. Sample 1difficulty 3/5

    To compare two histograms fairly, both should use

    • A

      Different bin counts

    • B

      Different scales

    • C

      Different x-axes

    • D

      Same axis scales (and bin widths)

      check_circle

    Why

    Common scales prevent visual misinterpretation when comparing distributions.

  2. Sample 2difficulty 3/5

    Two histograms show different distribution shapes.

    Two Distributions A: skewed right B: skewed left

    Which statement about A and B is correct?

    • A

      Both means equal both medians

    • B

      A's mean < A's median; B's mean > B's median

    • C

      Cannot determine without numbers

    • D

      A's mean > A's median; B's mean < B's median

      check_circle

    Why

    Right-skew: mean pulled right of median. Left-skew: mean pulled left of median.

  3. Sample 3difficulty 3/5

    Histograms A and B both have the same mean.

    Two Histograms A B

    Comparing the two distributions, which has a smaller standard deviation?

    • A

      A (more concentrated near center)

    • B

      B (more concentrated near center)

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    • C

      Cannot tell

    • D

      Both have equal SD

    Why

    Distribution B has more mass piled at the center with thinner tails, indicating less spread and a smaller SD.

  4. Sample 4difficulty 3/5

    Boxplots show salaries for male (M) and female (F) employees at one company.

    Salaries (1000s) M F

    Which comparison is best supported?

    • A

      Females have higher maximum

    • B

      Both have identical centers

    • C

      Males' median salary is higher than females'

      check_circle
    • D

      Males earn less on average

    Why

    The median line of M is to the right (higher) than the median line of F, indicating higher central salary for males.

  5. Sample 5difficulty 3/5

    Group A Group B

    From the side-by-side boxplots, the typical (median) value is larger for

    • A

      Group A (lower box)

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    • B

      Same

    • C

      Cannot tell

    • D

      Group B

    Why

    Group A's median line is at a smaller y (higher value if y-axis is value); choose by where the median sits.