Media aritmetica

Arithmetic mean is often used to average numerical data sets. It is calculated by adding all the values in the data set and dividing them by the total number of values, n. Here, the uppercase sigma indicates the sum of all the values.

For example, consider the daily screen time of students in a school. To find out the arithmetic mean, add up the screen time of all students and then divide the result by the total number of students. 

The study sample involves only a few students selected at random. The mean of such sample data is called the sample mean, denoted by x bar. 

Instead, if the data was collected from every student in the school, it becomes population data. The resulting population mean is denoted by mu.  

Since arithmetic mean considers every data value, it is considered representative of the data. But, a single extreme value can significantly change the mean, making it a very sensitive measure of center.