Two-way tables and conditional probability

Read joint and marginal frequencies and find the probability of one event given another.

Standards:8.SP.A.4S-CP.A.4

Try it: three questions

Real questions from the practice bank. Tap an answer to check it.

Question 1 of 3

A school surveyed 120 students about their favorite subject. The two-way table shows the results by grade level. | | Math | English | Science | Total | |---|---|---|---|---| | Grade 9 | 18 | 22 | 20 | 60 | | Grade 10 | 15 | 24 | 21 | 60 | | Total | 33 | 46 | 41 | 120 | If a student is randomly selected from those who prefer Science, what is the probability that the student is in Grade 9?

Question 2 of 3

A school surveyed 200 students about sports participation. Of the 80 students who play soccer, 50 also play basketball. Of the 120 students who do not play soccer, 30 play basketball. What is the probability that a randomly chosen student plays basketball given that they play soccer?

Question 3 of 3

A survey of 200 students asked whether they play soccer or basketball. 85 students play soccer, 60 play basketball, and 20 play both. How many students play soccer but not basketball?

How this fits in

Two-way tables and conditional probability is one skill in the Statistics & Probability unit. Students read the unit lesson, then earn a bronze, silver, or gold medal on their last 10 answers. Medals never go down. A mastered unit comes back for review after 1, 3, 7, 16, and 35 days so it stays learned.

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