1. Review HW
Questions?

2. Using Probability Formulas and Working Backwards
Lesson 10.5

3. Working with Formulas
Substitute in the information you have in to the appropriate formula.
Solve for the missing piece.
Use your algebra skills.

4. Probability Formulas Mutually Exclusive Independent Overlapping
P(A  B) = P(A) + P(B)
Independent
P(A  B) = P(A)  P(B)
Overlapping
P(A  B) = P(A) + P(B) – P(A  B)
Dependent
P(A  B) = P(A)  P(B|A)
Probability Formulas

5. Example 1 – Dependent P(A  B) = P(A)  P(B|A)
The probability of Sam getting an A on the Chemistry test is The probability of him getting an A on his Calculus test and an A on his Chemistry test is What is the probability of him getting an A on his Calculus test given that he got an A on his Chemistry test?
0.494 = 0.76  P(B|A)
0.65 = P(B|A)

6. Example 2 – Independent P(A  B) = P(A)  P(B)
An optional camp to improve players’ basketball skills was held in the county. The probability of a kid attending was The probability that they attended and made the honor roll was What is the probability that they made the honor roll?
0.44 = 0.62  P(B)
0.71 = P(B)

7. Example 3 – Overlapping (Inclusive) P(A  B) = P(A) + P(B) – P(A  B)
Find P(A  B)
P(B) = 5/8
P(A  B) = ¾
1/8 = P(A  B)

8. Worksheet Using Probability Formulas and Working Backwards
6 Problems