Edexcel Maths Unit 1 revision- updated

After request, a more complete guide to edexcel maths. Hope it's useful for your revision. Good luck!

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Unit 1 GCSE Maths- Edexcel
by Rachel Mander
Methods of Sampling
Random samples:
Names in a hat
Numbered participants- random numbers for each item, computer generated
Each item has an equal chance of being selected
Other
Check sample size
Check the time of when the sample is taken
Check when it is taken
Check ages of participants
Stratified sampling
Example
2000 small caps
4000 medium caps
3000 large caps
1000 extra large caps
Total= 10000
Sample= 50
Small= 2000 x 50 = 10 caps
10000
Medium= 4000 x 50= 20 caps
10000
Large= 3000 x 50= 15 caps
10000
Ex Large= 1000 x 50= 5 caps
10000
In General:
No. to Take= subgroup size x sample size
Total
Discrete Data
Is any data which can only take a value from a given list. This is counted e.g. siblings.
Continuous Data
Is any data which can take any value in a given range. This is measured. E.g. weight (can get more
accurate)
Quantitative Data
Above are both types of this data, measured or counted.
Qualititive Data
Mean

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Average
Add up data, divide by how many values
Mode
Most common
Most occurring value
Median
Middle in range
Middle value once ordered
Range
Difference between highest and lowest.
Raw Data Frequency Table Grouped Frequency Table
No. Of TVs
1, 5, 2, 3, 2, 3, 2,
3, 5 ,0, 2, 2, 3, 1, 1, 0, 4, 1, 2, No Tall Freq No. Of TV No. Tally Frequenc
3, 2, 3, 1, . y .…read more

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Average= 2580 (no. Of points)
36 (no. In group)
=71.6%
Quartiles
The Quartiles split the data into four sections, each containing the same number of pieces of data. This

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Box Plot
Outliers are values more than 1.5 times the interquartile range away from the nearest quartile.
If spread out more at lower end and clustered and the top it is a negative skew.
Vice versa is a positive skew.
It spread out equally, it is symmetrical.
Cummulative Frequency Diagram
On the table, the cumulative frequency is a column totalling the number of values entered in the

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Stem and Leaf
Example
A maths test is marked out of 50. The marks for the class are shown below:
7, 36, 41, 39, 27, 21
24, 17, 24, 31, 17, 13
31, 19, 8, 10, 14, 45
49, 50, 45, 32, 25, 17
46, 36, 23, 18, 12, 6
This data can be more easily interpreted if we represent it in a stem and leaf diagram.…read more

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This information is given to us in the Key. Remember the Key
It is usual for the numbers to be ordered. So, for example, the row
shows the numbers 21, 23, 24, 24, 25 and 27 in order.
Shows graphically the median group. Count in for median and mean you must do laboriously!
In the exam, do an unordered one first.
Probability
Independant Events
An event that doesn't affect another E.g. Roll a dice and a spinner, the spinners result dos not affect the

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From the tree diagram, we can see that there are eight possible outcomes. To find out the probability of
a particular outcome, we need to look at all the available paths (set of branches).
The sum of the probabilities for any set of branches is always 1.
Also note that in a tree diagram to find a probability of an outcome we multiply horizontally and add

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Graphs
Bar Graph
Discrete data. Gaps in between, separate figures, block labelled.
Histogram
Continuous data. No gaps. Range given, lines labelled. Individual bars are not labelled because the data is
continuous. Doesn't have to start at 0. To find the amount of people in half of a bar multiply the
frequency density by the class width wanted.
Frequency Polygon
Plotted at the midpoints of the bars on histograms. Don't join to the origin.…read more