Section 7 - Probability And Statistics Flashcards
What are all probabilitys between
0 and 1
How can you list all possible outcomes
A sample space diagram
When do the denominators in frequency trees change
The event is dependent
How to get end probabilities from a tree diagram
Multiply the branches
On a set of branches in a probability tree that meet at any point, what must the 2 numbers add to
1
To find probabilities from a Venn diagram you should
Convert to fractions by adding up all people in Venn diagram for denominator
What is the mode
Most common
What is the median
Middle value
How to find mode from a frequency table
The category with the most entries
How to find the range in a frequency table
Highest and lowest numbers from first column
How to find the median in a frequency table
Category containing middle value
How to work out mean using frequency table
3rd column total ÷ 2nd Column total
Third column in a frequency table equals
First column × second column
What are the upper/ lower quartile
1/4 and 3/4
How to find interquartile range
Difference between upper and lower quartile
How to plot a cumulative frequency graph
Add a culmative frequency column to graph given. The culmative frequency is just the frequency plus the frequencys that came before it.
E.g 4
9+4
13+20
33+42
Plot points using highest value in each class and the culmative frequency
Join with smooth curve
How to find upper/ lower quartile on cumulative graph. And the median
Go up 1/4 or 3/4 of the way
Go half way
What do histograms show
Frequency dencity
How to work out vertices axis on histogram
Frequency density = frequency ÷ class width
How do you find out how much a bar in a histogram represents
F = fd × class width = area of bar
In a scatter graph strong correlation =
Positive
The points are all close together
They are going upwards
Total of everything in pie chart =
360
For a stem and leaf diagram
The unit goes on the right and the ten number goes on the left
