Conditional probability
Work through restricted sample spaces, linked selections and conditional events. Explore the counts behind each answer.
Conditional proportions and reversed conditions
1 question · No time limit · Explore after checking
Example
Example
One member is chosen uniformly from Group A. What is the probability that this member answered Yes?
Group A has 7 members who answered Yes and 6 who answered No. Group B has 17 who answered Yes and 12 who answered No. Each member belongs to exactly one group.
| Yes | No | Total | |
|---|---|---|---|
| Group A | 7 | 6 | 13 |
| Group B | 17 | 12 | 29 |
| Total | 24 | 18 | 42 |
Choose an answer to try the example.
Why?
Within Group A, 7 of its 13 members answered Yes.
7/(7+6) = 7/13
Explore the idea
| Yes | No | Total | |
|---|---|---|---|
| Group A | 7 | 6 | 13 |
| Group B | 17 | 12 | 29 |
| Total | 24 | 18 | 42 |
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Choose an answer using the given information. Your first checked answer counts; showing the answer records 0 correct.
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About this practice
Learn a method
Condition on informationWork through restricted sample spaces, linked selections and conditional events. Explore the counts behind each answer.
For a broader mix of practices, explore the probability practice test. Membership is required to start a test.
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Optional and off by default. Share starts, completions, replays and error categories. For visits from ChatGPT, starts and completions can also include the first QuickenBrain page and broad country. No answers, drawings or names.
How this data is used