Data Processing - I
We know that collecting, organising and presenting the data make it more comprehensible. It facilitates data processing. But how do we analyse the data? There are a number of statistical techniques to analyse the data. These are:
Measures of Central Tendency
Measures of Dispersion, and
Measures of Correlation
Observation of the measurable characteristics such as rainfall, elevation, density of population and age groups may vary. We require a single value or number that best represents all the observations. This is done by finding out the centre of such observations. The statistical techniques to find out the centre of distributions are known as measures of central tendency.
Central tendency is measured by averages. An average is a single number used to represent the centre of a group of data. It is a value that describes the characteristics of the entire mass of data. It provides basis for analysis.
There are a number of measures of central tendency, such as mean, median and the mode.
Mean is the simple arithmetic average of the different values of a variable. It is the most common measure of central tendency. It is defined as the sum of values of a group of items divided by the number of items.
Median is the value of the middle item of a series, arranged in an ascending or descending order of magnitude. Median divides the series in two parts — one part containing values less than the median value and the other part contains values more than the median value.
Value which occurs most often in a series is called mode. The word mode is originated from a French word – la mode, which means fashion. Mode can be calculated in the individual series by inspection or by frequency distribution.