Question 4: What is meant by mean and standard deviation?
The mean or average is the sum of all the observations divided by the number of observations and gives a measure of the centrality of the data. The standard deviation is a measure of the scatter of the data about the mean value and is measured in the same units as the data itself. It is the square root of the variance where the variance of the sample is given by the sum of the squared deviations from the mean divided by the total sample size minus one.
Back to Exercise: Summarising Data.
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