Unit 9 - Independent Events

Independent Events

​WILL NEED CALCULATOR

Probabilities can also be used to calculate the likelihood of two events occurring at the same time.


You can calculate the probability of flipping heads on a coin AND then rolling a 2 on a dice.

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​These two events are called Independent Events

Independent events are events in which the outcome of one does not affect the outcome of the other. Flipping the coin does not change the outcome of rolling the dice

To calculate the probability of two independent events occurring, you multiply their theoretical probabilities together.

What is the probability that you flip a coin three times and it lands on heads all three times??

​What is the probability that you land on a letter, then a number, and then on green?

​8 total sections
3 letters, 5 numbers, and 2 green

Multiple Choice

What is the probability of drawing a blue marble, placing it back in the bag, and then selecting a green marble?

P(blue, green) = $$\frac{2}{11}\cdot\frac{4}{11}$$

• 6.6%

• 100%

• 55%

Multiple Choice

P(letter, number, letter) = ?

$$\frac{3}{8}\cdot\frac{5}{8}\cdot\frac{3}{8}=?$$

• 18%

• 26%

• 8.8%

Multiple Choice

What is the probability of flipping heads three times in a row and then flipping tails three times in a row?

$$\frac{1}{2}\cdot\frac{1}{2}\cdot\frac{1}{2}\cdot\frac{1}{2}\cdot\frac{1}{2}\cdot\frac{1}{2}=\frac{1}{64}=?\ \%$$

• 20%

• 1.5%

• 33%

Multiple Choice

If you spin the spinner twice, what is the probability of landing on an orange section and then a blue section?

$$\frac{3}{12}\cdot\frac{2}{12}=\frac{6}{144}=\ ?\ \%$$

• 4.2%

• 25%

• 16.7%

Multiple Choice

If you spin the spinner twice, what is the probability of landing on an even number and then an odd number?

$$\frac{5}{12}\cdot\frac{5}{12}=\frac{25}{144}=?\ \%$$

• 41.7%

• 2.6%

• 17.4%

Multiple Choice

Suppose you flip a coin and then roll a dice. What is the probability of flipping tails on the coin and then rolling a number less than 5 on the dice?

• 33.3%

• 41.7%

• 25%

Multiple Choice

What is the probability of rolling a 1 on a dice three times in a row?

• 4.6%

• 2.8%

• 0.5%