Data analysis and probability in Mathematics Achievement goes beyond basic averages.
Expected value is one idea met here: multiply each outcome by its probability and add the results. The probability of one event or another requires adding the two probabilities and subtracting the chance that both happen, so no outcome is counted twice. Overlapping groups use Venn diagrams, sometimes with three circles, where finding those in exactly one group means removing every overlap.
Other items read data from tables, bar graphs or stem-and-leaf plots and ask for the mean, median, mode or range. Choices often contain the total before overlaps were removed.
Sample questions
Pick an answer to see whether it is right — nothing is saved, and nothing needs an account.
Question 1Mid
A fair six-sided number cube is rolled twice. What is the probability that the sum of the two rolls is 9 or the product of the two rolls is 20?
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Answer: C — 91
The pairs with sum 9 are (3,6),(4,5),(5,4), and (6,3). The pairs with product 20 are (4,5) and (5,4), which are already included. There are 4 favorable outcomes out of 36, so the probability is 364=91.
Question 2Harder
A reward system gives exactly one of three point awards. The probability of receiving 2 points is 20%, and the probability of receiving 10 points is 25%. All remaining participants receive 6 points. What is the expected number of points received?
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Answer: C — 6.20
The probability of receiving 6 points is 100%−20%−25%=55%. Thus, the expected value is 2(0.20)+6(0.55)+10(0.25)=6.20.
Question 3Harder
At a school, 27 students belong to the robotics club, 23 belong to the debate club, and 19 belong to the art club. The pairwise overlaps are 10,8, and 7, and each includes the 3 students who belong to all three clubs. How many students belong to exactly one of the three clubs?
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Answer: C — 28
The pair-only regions contain (10−3)+(8−3)+(7−3)=16 students. Since there are 69 club memberships total, the number in exactly one club is 69−2(16)−3(3)=28.
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