# Maths- statistics 1

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- Created by: shona
- Created on: 26-12-12 16:13

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- Maths- statistics 1
- averages and range
- mode
- most common

- median
- the middle number once arranged in order

- mean
- the sum of all values divided by the total number of values in the set
- mean= sum of all values/ total number of values

- the sum of all values divided by the total number of values in the set
- range
- the difference between the highest and lowest values in a set
- range= highest-lowest

- the difference between the highest and lowest values in a set

- mode
- frequency tables
- when data is represented it can be put in a frequency table
- find the mode by looking for the data value that has the highest frequency
- find the median by adding up all the frequencies in order until half way point of all data is passed
- find the mean by multiplying the value of each data by its frequency adding the totals and dividing by the total of all the frequencies

- grouped data and frequency diagrams
- when there is a wide range of data with lots of values there are often too many entries for the frequency table
- so you will use a grouped frequency table

- in a grouped frequency table data is recorded in groups like 10< x<20
- grouped data can be shown in a frequency polygon
- the modal class is the group with the greatest frequency
- median cannot be found from grouped frequency tables
- calculate an estimated mean by adding the midpoints multiplied by the frequencies and dividing by the total frequency

- when there is a wide range of data with lots of values there are often too many entries for the frequency table
- histograms
- similar to a bar chart but continuous data only ( time or weight)
- the horizontal axis
- has the continuous scale and there are no gapes between the bars

- the area of each bar represents the frequency of the bar
- the height of the bar is called the frequency density
- frequency density= frequency class interval/ width of class interval

- the median is the value where the area of both is equal
- the lower quartile is the value that splits the area in the ratio 1:3
- the upper quartile is the value that splits the area in the ratio 3:1

- the data handling cycle
- outlining the problem and planning
- usually involves a hypothesis

- stating how the data will be collected
- saying how the data will be processed and represented
- usually involve working out means and measures of spread and showing the data in a suitable diagram

- interpreting the results and making a conclusion
- this should relate to the original hypothesis or problem

- outlining the problem and planning
- data and data collection
- qualitive
- this is data such as colour of cars

- discrete quantative
- this is numerical data that can only take certain values such as the number of people on a bus

- continuous quantative
- this is numerical data that can take any value in a range of values such as the weight of apples

- primary data
- this is data collected using surveys or experiments

- secondary data
- this is data collected from existing tables or lists

- look at historical data
- this would be used to predict whether it will rain on the 4th july in Edinburgh for example you would look back at records for all previous years

- experiment
- this would be used to test the probability of an event that cannot be predicted such as how many blue balls in a bag

- equally likely outcomes
- this is used when the probability of an event can be predicted for example taking a king from a pack of cards

- surveys
- this is used when there is no historical data and no way to predict probabilities a survey could be used to find what subject is the favourite amongst year 7 pupils

- qualitive

- averages and range
- when talking about the average its the same as the mean
- the lower quartile is the value that splits the area in the ratio 1:3
- there are four parts to the data handling cycle
- usually involve working out means and measures of spread and showing the data in a suitable diagram
- there are different types of data
- depending on what is being investigated there are four different ways to collect data

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