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One-Variable Data: Distributions and Measures of Center and Spread Flashcards

7 cards from real Bluebook SAT Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 One-Variable Data: Distributions and Measures of Center and Spread flashcards as text

  1. Which of the following changes would NOT affect the median of a dataset?

    Answer: Changing the largest value to an even larger number

    Changing only the largest value (which is already above the median) does not move the middle position, so the median is unaffected.

  2. A dataset has values 10, 20, 30, 40, and 50. The mean is 30 and the range is 40. If every value is increased by 5, the new mean and range are:

    Answer: Mean=35, Range=40

    Adding 5 to every value increases the mean by 5 (to 35) but does not change the range, since max and min both shift by the same amount.

  3. A frequency histogram shows test scores. The bars have heights: 50-59: 2 students, 60-69: 4 students, 70-79: 8 students, 80-89: 6 students, 90-99: 2 students. What is the modal class?

    Answer: 70-79

    The modal class is the interval with the highest frequency; the 70-79 interval has 8 students, the most of any group.

  4. The mean of a dataset is 25 and the standard deviation is 5. If a value of 40 is added to the dataset, what happens?

    Answer: Mean increases; standard deviation increases

    Adding 40 (above the mean) pulls the mean upward and also increases the spread since 40 is far from the current center.

  5. The data set {5, 8, 10, 12, 15} has a mean of 10. Which value, if replaced by 30, would cause the greatest increase in standard deviation?

    Answer: 10

    Replacing the middle value (10, which equals the mean) with 30 creates the greatest deviation from the mean for that position, maximally increasing spread.

  6. A box plot shows: Min=5, Q1=15, Median=22, Q3=30, Max=42. Which interval contains approximately 50% of the data?

    Answer: 15 to 30

    The box (Q1 to Q3) in a box plot represents the middle 50% of the data, from 15 to 30.

  7. A teacher calculates class mean scores: Quiz 1 mean = 70, Quiz 2 mean = 80. The class took both quizzes with 20 students each. What is the mean score across both quizzes combined?

    Answer: 75

    Since both groups are the same size (20 students), the combined mean is simply (70 + 80) / 2 = 75.