Algebra 2H
10.2 Day 2 and 10.3 Day 1
Name: __________________________
Date: _______________
Conditional Probability
A quality control inspector checks for defective parts. The table shows the results of the inspector’s work.
Defective
Non-defective
Pass
5
208
Fail
24
9
What is the Probability that a defective part passes? What is the Probability that a non-defective part passes?
A clothing store finds that 75% of its customers buy pants. Twenty percent of their customers buy pants and a belt.
What is the Probability that a customer who buys pants also buys a belt?
Finding Joint, Marginal, Relative and Conditional Relative Frequencies
Amount of Fresh
Water Should
Be Reduced
Joint Frequency: each entry in the main
2 x 2 table
Yes
Fish
Marginal Frequency: the sums of the
rows and columns (joint frequencies)
No
Total
Yes
No
Total
Amount of Fresh
Water Should
Be Reduced
Joint Relative Frequency: the ratio of
the joint frequency to the total
number of values, expressed as a
decimal
Fish
Marginal Relative Frequency: the
sums of the rows and columns (joint
relative frequencies)
Yes
No
Total
Yes
No
Total
Conditional Relative Frequency is the ratio of a
Joint Relative Frequency to one of the Marginal
Relative Frequencies.
Amount of Fresh Water
Should Be Reduced
Fish
Yes
Yes
No
No