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Data Analysis & Statistics Flashcards

7 cards from real AMC 8 practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Data Analysis & Statistics flashcards as text

  1. The average of 6 numbers is 12. When one number is removed, the average of the remaining 5 is 11. What number was removed?

    Answer: 17

    Total of 6 numbers = 72; total of remaining 5 = 55; the removed number = 72−55 = 17.

  2. Five quiz scores are 62, 75, 80, 85, and 88. If the lowest score is removed, by how much does the mean increase?

    Answer: 4

    Original mean = 390/5 = 78; new mean = 328/4 = 82; the increase is 82−78 = 4.

  3. A histogram has intervals with frequencies: 0–10: 3, 10–20: 8, 20–30: 12, 30–40: 5. In which interval does the median fall?

    Answer: 20–30

    Total = 28 values; the 14th and 15th values fall in the 20–30 interval (cumulative through 20 is 11).

  4. A data set of 8 values has a sum of 96. Three new values of 10, 12, and 14 are added. What is the new mean?

    Answer: 12

    New sum = 96+10+12+14 = 132; new count = 11; mean = 132/11 = 12.

  5. In a box plot, Q1 = 20, median = 30, Q3 = 40, minimum = 10, maximum = 60. What is the interquartile range (IQR)?

    Answer: 20

    IQR = Q3 − Q1 = 40 − 20 = 20.

  6. The mean of a data set is 15 and the median is 13. If the largest value (an outlier of 30) is removed, what is most likely true?

    Answer: The mean decreases more than the median

    Removing a large outlier has a greater effect on the mean (which depends on all values) than on the median (which depends only on position).

  7. Students earn these scores on a 10-question quiz: five students score 6, three score 8, two score 10. What is the mean score?

    Answer: 7.4

    Total = 5×6 + 3×8 + 2×10 = 30+24+20 = 74; mean = 74/10 = 7.4.