Statistical Landmarks

When we count, measure, ask questions, observe and describe, the information we collect is called data. 

For example, let’s collect the month that each member of a baseball team was born. There are 9 players. The months are: 

8, 2, 5, 7, 2, 10, 4, 5, 1 

Landmarks are used to describe the set of data: 

The minimum is the smallest value of the data.  

The maximum is the largest value of the data. 

The range is the difference between the minimum and the maximum. 

The mode is the value(s) that occurs most often. 

The median is the middle value (not the average). 

To find the median, arrange the numbers from smallest to largest. Then, start crossing the numbers off from each end of that list. 

1  2  2  4  5  5  7  9 10 

The mean is the average value. 

To find the average, add up all the numbers and divide that answer by the number of numbers. In our example, the sum of all 9 numbers is: 45. Then divide 45 by 9. The mean is: 5 

In our example: 

 Note: The mean and the median are not always the same !!!