Statistics – Mean:
We are aware of the term average during our schooling. In statistics , when dealing with set of quantitative data we term it as mean. It is computed by adding all the values in the data set divided by the number of observations in it.
Mean can be represented using the formula:
Mean() = Sum of all values/Number of values =
Mean of population is denoted by ‘µ’ and Mean of sample is denoted by ‘’.
Number of items in population is ‘N’ and in a sample it is ‘n’.
The mean uses each and every value in the dataset and hence is a good representative of the data. Repeated samples drawn from the same population tend to have similar means. Calculating mean eliminates random errors and helps to derive a more accurate result. Therefore the mean is considered as the best measure of central tendency that resists the fluctuation between different samples. The limitation of mean is that it is sensitive to extreme values/outliers, especially when the sample size is small.
Example:
Student id | Marks in math |
a01 | 75 |
a02 | 70 |
a03 | 72 |
a04 | 83 |
a05 | 80 |
a06 | 86 |
a07 | 77 |
a08 | 88 |
Applying the formula we have mean = 75+70+72+83+80+86+77+88/8 =631/8 =78.875
Let’s find out mean of a dataset in Excel
We have function AVERAGE(start value : end vale)