How do you find a probability from a Venn diagram that shows frequencies?

Add together the frequencies in the regions you want, then divide by the total frequency. If the diagram lists individual elements instead of frequencies, count the elements you want and divide by the total number of elements.

Where do the items that are in neither set go on a Venn diagram?

Inside the rectangle but outside both circles. They still count towards the total, so they must be included in the denominator when you work out a probability.

True or False? Writing a list systematically means there is some sort of order to the list.

True. Writing a list systematically means there is some sort of order to the list. It is not the same as trying to write out a list randomly.

True or False? Writing a list systematically means it is impossible to miss out an option.

True. Writing a list systematically means it is impossible to miss out an option. Systematic means the list was created in an organised way.

ZYX is a possible arrangement of the letters XYZ. Create a systematic way to list all the arrangements of the letters XYZ.

For example, make the first letter an X and swap the other two: XYZ, XZY. Then make the first letter a Y and swap the other two: YXZ, YZX. Finally, make the first letter a Z and swap the other two: ZXY, ZYX. All the arrangements are: XYZ, XZY, YXZ,YZX, ZXY, ZYX. (There are other acceptable ways to create an organised list like this).

True or False? A bag contains ten green (G) marbles and ten red (R) marbles. Two marbles are selected at random. The possibilities are GR or RG.

False. There are ten green (G) marbles and ten red (R) marbles. Two marbles selected at random might both be green, or both be red. The possibilities are actually GR, RG, GG or RR.

What is a sample space in the context of probability?

A sample space is the set of all possible outcomes of an experiment. It may be a list or a grid showing all the possible outcomes.

True or False? You can always use a sample space grid to represent all possible outcomes .

False. When combining more than two things , you may need to go back to listing outcomes instead of using a grid.

How do you calculate probabilities using a sample space ?

Count the possibilities you want , then divide by the total number of possibilities in the sample space. (Note: this only works if every possibility in the sample space is equally likely .)

IGCSEMathsEdexcelMaths AFoundationFlashcards6. Statistics & ProbabilityVenn Diagrams & Sample Space Diagrams

Venn Diagrams & Sample Space Diagrams (Edexcel IGCSE Maths A: Foundation): Flashcards

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How do you find a probability from a Venn diagram that shows frequencies?

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How do you find a probability from a Venn diagram that shows frequencies?
Add together the frequencies in the regions you want, then divide by the total frequency.
If the diagram lists individual elements instead of frequencies, count the elements you want and divide by the total number of elements.
True or False?
The probability of being in $A$ but not $B$ uses the whole of the $A$ circle.
False.
The overlap must be left out, because those elements are in $B$ as well.
Only the part of the $A$ circle lying outside the intersection counts.
10 people have a cat, 8 people have a dog, and 6 people have both. Complete the numbers for the Venn diagram:
Cat but not dog: $______$
Dog but not cat: $______$
The completed numbers are:
Cat but not dog: 4
Dog but not cat: 2
The 6 people who have both are already counted within the 10 and within the 8, so they are subtracted from each.
Where do the items that are in neither set go on a Venn diagram?
Inside the rectangle but outside both circles.
They still count towards the total, so they must be included in the denominator when you work out a probability.
In a class of 30, 15 study Spanish and 3 of those also study German. What is the probability that a student studies Spanish but not German?
The probability is $\frac{12}{30}$ , which simplifies to $\frac{2}{5}$ .
Of the 15 studying Spanish, 3 also take German, which leaves 12 taking Spanish only.
True or False?
Writing a list systematically means there is some sort of order to the list.
True.
Writing a list systematically means there is some sort of order to the list.
It is not the same as trying to write out a list randomly.
True or False?
Writing a list systematically means it is impossible to miss out an option.
True.
Writing a list systematically means it is impossible to miss out an option.
Systematic means the list was created in an organised way.
ZYX is a possible arrangement of the letters XYZ.
Create a systematic way to list all the arrangements of the letters XYZ.
For example, make the first letter an X and swap the other two: XYZ, XZY.
Then make the first letter a Y and swap the other two: YXZ, YZX.
Finally, make the first letter a Z and swap the other two: ZXY, ZYX.
All the arrangements are: XYZ, XZY, YXZ,YZX, ZXY, ZYX.
(There are other acceptable ways to create an organised list like this).
True or False?
A bag contains ten green (G) marbles and ten red (R) marbles.
Two marbles are selected at random.
The possibilities are GR or RG.
False.
There are ten green (G) marbles and ten red (R) marbles.
Two marbles selected at random might both be green, or both be red.
The possibilities are actually GR, RG, GG or RR.
What is a sample space in the context of probability?
A sample space is the set of all possible outcomes of an experiment.
It may be a list or a grid showing all the possible outcomes.
True or False?
You can always use a sample space grid to represent all possible outcomes.
False.
When combining more than two things, you may need to go back to listing outcomes instead of using a grid.
How do you calculate probabilities using a sample space?
Count the possibilities you want, then divide by the total number of possibilities in the sample space.
(Note: this only works if every possibility in the sample space is equally likely.)

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