The population mean could be defined as the average of a group characteristics. The group can include a person, a thing, or an item etc. for example, you may have to find population mean for a set of people living in USA or all dog in the Georgia and more. So, a characteristic is just an item of interest. For example, books in the library are usually checked seven times every year on an average.

In statistics, population mean is calculated rarely as it is quite time consuming and costly too. Take one more example here if you wanted to calculate the average weight of a dog then will you be tracking 70-80 million dogs together. The best idea here is taking a sample and weight them. The population mean formula in mathematics could be given as –

\[\large \mu=\frac{\sum x_i}{N}\]

Where,

x_{i} = Sum of the values

*N*=number of the value

When you are calculating population mean, you could realize that it is very similar to the average that we have learned in the case of basic mathematics. However, you need to extra cautious when taking the mean for a population not the sample. Here we are giving the symbols for both – the population mean and the sample mean that are frequently used with statistics.

You should take the ratio in case of