Data is a set of values which gives some information. Collection of data means to collect the data from the different resources which gives some specific information. Presentation of data in a variety of formats such as tables, graphs, maps, diagrams illustrations, flow charts etc. is called organisation of data.
Average is a representative value expressing the central value in a set of data. Arithmetic mean is one of the representative values of data. It is defined as the sum of all the observations divided by the total number of observations. The mean lies in between the greatest and the smallest observations.
Range of a data is the difference between the highest and the lowest observations.
Mode is another type of measure of central tendency. Mode of a set of data is simply the value in the set that occurs most often. If the number of observations is large, then we put the same observations together and count them by the tabulation method. A set of data may not have any mode at all. A set of data can have more than one mode. Such type of data is said to be multimodal data.
There is another type of central of tendency namely median. The median divides the whole data into two equal parts. It is the mid value in the ordered series of data.
A bar graph is a graphical representation of data by the number of rectangles of equal width. Double bar graph is a graph that uses pairs of bars to compare and show the relationship between two sets of data.
Probability is a branch of mathematics that deals with calculating the likelihood of a given event's occurrence, which is expressed as a number between 0 and 1. An event having probability 0 is an impossible event. An event having probability 1 is a sure event.