Transcript Probability of Independent Events

Probability of Independent
Events
Section 11.5
Vocabulary
• Independent event - two events whose
occurrence of one event DOES NOT affect the
likelihood that the other event will occur
• Examples:
– Fliping a coin and spinning a spinner
– drawling a marble, replacing it, and then drawling
another marble
– a girl puppy is born first and a boy puppy is born
second
Things to Know
Finding the Probability of Two
Independent Events
Step 1:
Find the probability of A = P(A)
Step 2:
Find the probability of B = P(B)
Step 3:
Multiply the probability of A by the probability of B =
P(A) x P(B)
Step 4:
Simplify your fraction
Example 1
A number cube is rolled and a coin is tossed.
Find the probability of rolling a 2 and landing on
heads.
Your Turn
A number cube is rolled and the spinner is
spun. Find the probability of rolling an even
number and spinning a 4.
Example 2
To win the grand prize, Ted has to choose one
of 10 keys to match with one of 3 treasure
chests. What are Ted’s chances of winning?
Your Turn
Sarah placed 4 yellow chips and 8 pink chips
into a bag. She selected 1 chip without
looking, replaced it, and then selected a
second chip. Find the probability that she
first selected a yellow chip and then selected
a pink chip.
Example 3
A coin is tossed, and the spinner shown is
spun. Find the probability of tossing heads
and spinning a 3.
Your Turn
•
Find the probability of each event.
1. P(tails and even)
2. P(heads and less than 4)
Assignment
• Page 452 #9-13, #17-25, skip #23 in red textbook