Unit 4 sec 4.1 Range

Unit 4 sec 4.1 Range 

12 December 2015

22:36

 As you have just seen, simple way of estimating spread is to scan along the data to find this marvellous (minimum, all min) and largest (maximum of Max) values. The range is the difference between these 2 values. In other words,

Range = Max –min.

Example 2   calculating the range

work at the data below, which against the distances, in kilometres, travelled by allowing students to attend an open University tutorial.

Distances from home

distance (Km): 12 40 26 4 2 18 66 30 45 12 15

calculate the range of this data

solution

by inspecting the data, the maximum value is 66 km and the minimum value is 2 km.

so the range of these data is

Max – min = 66 km – 2 km = 64 km.

the range is sometimes a rather inadequate major of spread, particularly where there are one or two extreme outliers in the dataset. In the jargon of statistician, the range can be referred to as a “quick and dirty” measure of spread - it is quick and easy to calculate, and sometimes do a useful overall impression.