Measures of dispersion for discrete data (AQA GCSE Statistics): Flashcards
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Practise the cards
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What is the formula for calculating range?
What is the formula for calculating range?
Range = largest value - smallest value
How do you find Q₁ in a dataset of 12 values?
How do you find Q₁ in a dataset of 12 values?
Q₁ position = (12+1)/4 = 3.25, find between 3rd & 4th
What does IQR represent in a dataset?
What does IQR represent in a dataset?
IQR = Q₃ - Q₁, shows middle 50% of data spread
How to calculate Q₃ for 20 data points?
How to calculate Q₃ for 20 data points?
Q₃ position = 3(20+1)/4 = 15.75, find between 15th & 16th
What is the first step in finding quartiles?
What is the first step in finding quartiles?
Order your data from smallest to largest
Why is the range sometimes misleading?
Why is the range sometimes misleading?
It only considers extreme values, ignoring others
How to find quartiles from a frequency table?
How to find quartiles from a frequency table?
Use cumulative frequency to locate quartile positions
What is cumulative frequency in a frequency table?
What is cumulative frequency in a frequency table?
It shows the total number of observations up to each value.
What is a common mistake when finding quartiles?
What is a common mistake when finding quartiles?
Not ordering data first before calculations
What does Q₂ represent in quartiles?
What does Q₂ represent in quartiles?
Q₂ is the median, dividing data into two equal halves