Venn diagrams and probability
The Maths Habit
Where does each shape go?
Work these out.
3 + 2 + 4 + 1105 + 1 + 2 + 6144 + 3 + 7 + 2163 red, 4 blue. P(red)?37
- Venn diagram
- Circles in a box that sort things into groups. Everyone is somewhere in the box.
- Both
- In both circles: the middle.
- Only
- In one circle, not the middle.
- Neither
- In no circle: outside the circles, in the box.
- At random
- Without looking, so each one has the same chance.
1all2ones you want3P(both) =ones you wantall
- 1Add all the numbers.The one outside too. This goes on the bottom.
- 2Find the ones you want.Shade them. This goes on the top.
- 3Write the fraction.Put the top over the bottom.
One person is picked at random. Find P(both).
1Add all the numbers.
2 + 3 + 4 + 1 =102Find the ones you want.
33Write the fraction.
P(both) =310in the middleall
One person is picked at random. Find P(neither).
1Add all the numbers.
5 + 1 + 3 + 2 =112Find the ones you want.
23Write the fraction.
P(neither) =211outside the circlesall
One person is picked at random. Find P(both).
1Add all the numbers.
2 + 3 + 4 + 1 =102Find the ones you want.
33Write the fraction.
P(both) =310in the middleall
1Add all the numbers.2Find the ones you want.3Write the fraction.
One person is picked at random. Find P(dance only).
1Add all the numbers.
3 + 2 + 4 + 2 =112Find the ones you want.
43Write the fraction.
P(dance only) =411only in Danceall
One person is picked at random. Find P(both).
1Add all the numbers.
2 + 3 + 4 + 1 =102Find the ones you want.
33Write the fraction.
P(both) =310in the middleall
1Add all the numbers.2Find the ones you want.3Write the fraction.
One person is picked at random. Find P(both).
1Add all the numbers.
4 + 1 + 5 + 3 =132Find the ones you want.
13Write the fraction.
P(both) =113in the middleall
One person is picked at random. Find P(both).
1Add all the numbers.
2 + 3 + 4 + 1 =102Find the ones you want.
33Write the fraction.
P(both) =310in the middleall
1Add all the numbers.2Find the ones you want.3Write the fraction.
One student is picked at random. Find P(neither).
1Add all the numbers.
6 + 2 + 1 + 4 =132Find the ones you want.
43Write the fraction.
P(neither) =413outside the circlesall
1Add all the numbers.2Find the ones you want.3Write the fraction.
1Find P(both).
1Add all the numbers.
2 + 1 + 4 + 3 =102Find the ones you want.
13Write the fraction.
P(both) =110in the middleall
2Find P(tea only).
1Add all the numbers.
3 + 4 + 2 + 2 =112Find the ones you want.
33Write the fraction.
P(tea only) =311only in Teaall
3Find P(neither).
1Add all the numbers.
5 + 2 + 3 + 3 =132Find the ones you want.
33Write the fraction.
P(neither) =313outside the circlesall
One person is picked at random. Find P(football).
1Add all the numbers.
4 + 3 + 2 + 2 =112Find the ones you want.
4 + 3 =73Write the fraction.
P(football) =711in the Football circleall
One person is picked at random. Find P(dance).
1Add all the numbers.
2 + 3 + 5 + 1 =112Find the ones you want.
3 + 5 =83Write the fraction.
P(dance) =811in the Dance circleall
One person is picked at random. Find P(football).
1Add all the numbers.
4 + 3 + 2 + 2 =112Find the ones you want.
4 + 3 =73Write the fraction.
P(football) =711in the Football circleall
1Add all the numbers.2Find the ones you want.3Write the fraction.
One person is picked at random. Find P(pizza).
1Add all the numbers.
3 + 2 + 4 + 4 =132Find the ones you want.
3 + 2 =53Write the fraction.
P(pizza) =513in the Pizza circleall
One person is picked at random. Find P(football).
1Add all the numbers.
4 + 3 + 2 + 2 =112Find the ones you want.
4 + 3 =73Write the fraction.
P(football) =711in the Football circleall
1Add all the numbers.2Find the ones you want.3Write the fraction.
One person is picked at random. Find P(car).
1Add all the numbers.
1 + 4 + 3 + 2 =102Find the ones you want.
4 + 3 =73Write the fraction.
P(car) =710in the Car circleall
One person is picked at random. Find P(football).
1Add all the numbers.
4 + 3 + 2 + 2 =112Find the ones you want.
4 + 3 =73Write the fraction.
P(football) =711in the Football circleall
1Add all the numbers.2Find the ones you want.3Write the fraction.
One person is picked at random. Find P(fruit).
1Add all the numbers.
2 + 2 + 5 + 2 =112Find the ones you want.
2 + 5 =73Write the fraction.
P(fruit) =711in the Fruit circleall
Is it right?
Thumbs up: right. Thumbs down: wrong.
P(both) = 215
Right
P(neither) = 411
Wrong: the bottom is all 15
P(red only) = 615
Right
P(red) = 615
Wrong: the top is 6 + 2 = 8
P(blue only) = 315
Right
30 students: 17 play chess, 12 play draughts, 5 play both. Draw the Venn diagram.
12, 5, 7, 6
Find P(plays exactly one of the games).
1930
Find P(plays neither). Simplify it.
630 = 15
One person is picked at random. Find P(both).
310
One person is picked at random. Find P(juice).
611ξMilkJuice32421All2Juice3P(juice) =
Exit tickets to print