Table of contents
- 1. Intro to Stats and Collecting Data55m
- 2. Describing Data with Tables and Graphs1h 55m
- 3. Describing Data Numerically1h 45m
- 4. Probability2h 16m
- 5. Binomial Distribution & Discrete Random Variables2h 33m
- 6. Normal Distribution and Continuous Random Variables1h 38m
- 7. Sampling Distributions & Confidence Intervals: Mean1h 3m
- 8. Sampling Distributions & Confidence Intervals: Proportion1h 12m
- 9. Hypothesis Testing for One Sample1h 1m
- 10. Hypothesis Testing for Two Samples2h 8m
- 11. Correlation48m
- 12. Regression1h 4m
- 13. Chi-Square Tests & Goodness of Fit1h 20m
- 14. ANOVA1h 0m
4. Probability
Multiplication Rule: Independent Events
Problem 3.2.6
Textbook Question
True or False? In Exercises 5 and 6, determine whether the statement is true or false. If it is false, rewrite it as a true statement.
6. If events A and B are dependent, then P(A and B) = P(A) · P(B).

1
Step 1: Begin by understanding the concept of dependent and independent events. Dependent events are those where the occurrence of one event affects the probability of the other. Independent events, on the other hand, do not influence each other.
Step 2: Recall the formula for the probability of the intersection of two events (A and B). For independent events, the formula is P(A and B) = P(A) · P(B). However, for dependent events, this formula does not hold because the probability of B depends on A.
Step 3: For dependent events, the correct formula is P(A and B) = P(A) · P(B|A), where P(B|A) is the conditional probability of B given that A has occurred.
Step 4: Compare the given statement, 'If events A and B are dependent, then P(A and B) = P(A) · P(B)', with the correct formula for dependent events. Notice that the statement is false because it uses the formula for independent events instead of the correct formula for dependent events.
Step 5: Rewrite the statement as a true statement: 'If events A and B are dependent, then P(A and B) = P(A) · P(B|A).' This correctly reflects the relationship between dependent events.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Dependent Events
Dependent events are two or more events where the occurrence of one event affects the probability of the other event(s). For example, drawing a card from a deck without replacement means the outcome of the first draw influences the probabilities of subsequent draws.
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Joint Probability
Joint probability refers to the probability of two events occurring simultaneously. For dependent events A and B, the joint probability is calculated differently than for independent events, as it takes into account the influence of one event on the other.
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Independent Events
Independent events are those where the occurrence of one event does not affect the probability of the other event. For independent events A and B, the joint probability is given by P(A and B) = P(A) · P(B), which is not applicable for dependent events.
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