4.3.8 Standard Deviation Flashcards
What is the mean?
A mean value is what is usually meant when the term “average” is used in biology
Mean = sum of all measurements ÷ number of measurements
Problems with the mean occur when there are one or two unusually high (or low) values in the data (outliers) which can make the mean too high (or too low) to reflect any patterns in the data
The mean is sometimes referred to as X̄ in calculations
What is standard deviation?
The mean is a more informative statistic when it is provided alongside the standard deviation
Standard deviation measures the spread of data around the mean value
It is very useful when comparing consistency between different data sets
The mean must be calculated before working out the standard deviation
Look at SME for calculation.
