Write down the probability of getting the same on both coins.

1/2

What happens if one or both of the coins is biased?

You

need to add a lot more rows/columns.

The sample space below shows the result of flipping two coins.

Write down the probability of getting the same on both coins.

What happens if one or both of the coins is biased?

**Tree Diagrams and Independent events**

Starter

Using tree diagrams

Tree diagrams

Two biased coins are flipped. The probability of heads on the first coin is 0.6. The probability of heads on the second coin is 0.75. Show the probabilities of the four possible outcomes.

Work out the probability of getting two coins the same.

**L.O. - Use tree diagrams to find the probability of combined events.**

Starter

H

T

H

H

T

T

P(H, H)

P(H, T)

P(T, H)

P(T, T)

0.6

0.75

0.75

Tree diagrams

Two biased coins are flipped. The probability of heads on the first coin is 0.6. The probability of heads on the second coin is 0.75. Show the probabilities of the four possible outcomes.

Work out the probability of getting two coins the same.

0.15 + 0.3 = 0.45

H

T

H

H

T

T

P(H, H) = 0.45

P(H, T) = 0.15

P(T, H) = 0.3

P(T, T) = 0.1

0.6

0.75

0.75

0.4

0.25

0.25

Team A and B play each other in the league home and away. Each game can be win, lose or draw. Draw a tree diagram to show the possible outcomes for Team A.

The probability that team A win their home game is 0.7. The probability of a draw is 0.12. The probability that team A win their away game is 0.4. The probability of a draw is 0.38. Work out the probability that Team A get the same result from both games.

Using tree diagrams

Team A and B play each other in the league home and away. Each game can be win, lose or draw. Draw a tree diagram to show the possible outcomes for Team A.

The probability that team A win their home game is 0.7. The probability of a draw is 0.12. The probability that team A win their away game is 0.4. The probability of a draw is 0.38. Work out the probability that Team A get the same result from both games.

W

W

W

W

D

D

D

D

L

L

L

L

0.7

0.12

0.18

0.4

0.4

0.4

0.38

0.38

0.38

0.22

0.22

0.22

P(W,W) = 0.28

P(D,W) = 0.048

P(L,W) = 0.072

P(W,D) = 0.266

P(D,D) = 0.0456

P(D,D) = 0.0684

P(W,L) = 0.154

P(D,L) = 0.0264

P(L,L) = 0.0396

0.28 + 0.048 + 0.072 = 0.4

Activity

Complete the tree diagram worksheet

Plenary

Complete the exam question.

Plenary

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