Download Independent Events

Warm Up
What is the theoretical probability of
rolling a die and landing on a
composite number?
Independent Events
March 7, 2014
Independent Events
Outcome
of one event DOES
NOT affect the outcome of
another event.
P(A and B)
= P(A) • P(B)
Example
Find the probability of
flipping a coin twice and
getting 2 tails.
 First P(T) = ½
 Second P(T) = ½
P(T,T)
=
1 1
∙
2 2
=
1
4
With Replacement
A bag has 10 marbles:
5 blue
3 red
2 green
What is the probability
of picking
a red marble from the bag?
 If I put the marble back in the
bag, what is the probability of
picking a green marble?
Without Replacement
 What
if I picked a red marble and did
not put it back in the bag? Would the
probability of picking a green marble
change?
 YES
 NOT INDEPENDENT
Are the events independent?
Rolling
a die and flipping a coin
Picking three cards, one at a
time without replacing them
Spinning a spinner 3 times
LET’S PLAY SLAP IT!!!
Look at the spinner below.
Imagine you spin the spinner two times
in a row. What is the probability of
landing on a 4 and then a 7?
You reach into a bag of skittles. The
bag contains 4 red, 2 green,
1 yellow, and 3 blue skittles. You
reach into the bag and pull out a
skittle and then put it back into the
bag. What is the probability that
you will choose a yellow and then a
blue skittle?
The probability of seeing a
1
red car on the road is .
12
What is the probability of
seeing a car that is NOT red?
You roll a 6 sided dice three
times. What is the
probability that you will roll
a 1, 2, and then an even
number?
You are flipping a coin. You flip
the same coin 3 times in a row.
What is the probability that you
will land on a heads, a tails, and
then a heads?
You flip a coin and toss a die.
What is the probability of getting
not tails and then NOT 1?
Look at the spinners below:
If you spin each spinner one time, what
is the probability that you will land on an
odd number and the letter B?
Sally is deciding what to wear
tomorrow to school. She can
wear a blue, purple, pink, or
yellow top. She can wear jeans or
capris on the bottom. How many
outfit combinations of tops and
pants can she make?
The probability that you will
draw a yellow ball out of a bin
is 1/3. If there are 12 balls in
the bin, how many are yellow?
Sarah wants to have dessert. She has an option of
brownies, cookies, or ice cream. She can also choose
milk or water to drink. Which tree diagram shows all
of the options for Sarah’s dessert and drink?
A1
Brownies
Cookies
B2
milk
Milk
Milk
Brownies
3C
Milk
Brownies
Water
Water
Milk
Milk
Cookies
Cookies
Water
Water
Milk
Ice Cream
Milk
Ice Cream
Water
Water
Milk
If the numbers 1 through 10 are
placed in a box, what is the
probability that you will randomly
choose a number that is a factor
of 12?
You reach into a jar or marbles.
The jar contains 5 pink, 2 green, 6
blue, 4 purple, and 3 yellow
marbles. What is the probability
that you will reach into the jar and
pull out a marble that is NOT
purple?
Tell Your Neighbor:
If Miss Delaney pulls a popsicle
stick from your class’ bucket,
replaces it and pulls another
stick, is that an independent or
dependent event? How do you
know?