# Finding a probability based on a table

1. How many ways can 15 girls be chosen to form a baseball team (need 9 players)?

5005

1,816,214,400

24

135

3. Use this table to answer questions #3 through #6. Some students were asked if they carry a credit card. Here are the responses.

Class______ | Credit Card Carrier | Not a Credit Card Carrier | Total

Freshman______________33_______________________27________________60

Sophomore______________6_______________________34________________40

Total__________________39_______________________61________________100

What is the probability that the student didn't carry a credit card?

4. What is the probability that the student is a freshman and carries a credit card?

5. What is the probability that the student is a sophomore given he doesn't carry a credit card?

6. Are Credit Card Carriers and Freshmen independent events? Prove this mathematically

#### Solution Preview

1. How many ways can 15 girls be chosen to form a baseball team (need 9 players)?

5005

1,816,214,400

24

135

Solution. The number ways is

C(15, 9)=15!/[9!*6!]=5005

So, the first answer is correct.

3. Use this table to answer questions #3 through #6. Some students were asked if they carry a credit card. Here are the responses.

Class______ | Credit Card Carrier | Not a Credit Card Carrier | ...

#### Solution Summary

This solution contains a detailed explanation of finding a probability based on a table.