Answer:
The standard deviation is the average amount of variability in your data set. It tells you, on average, how far each score lies from the mean.
The standard deviation measures the spread of the data about the mean value. It is useful in comparing sets of data which may have the same mean but a different range. For example, the mean of the following two is the same: 15, 15, 15, 14, 16 and 2, 7, 14, 22, 30. However, the second is clearly more spread out.
Step-by-step explanation: