What is Statistics?

Statistics deals with the collection, the classification, the analysis and the interpretation of numerical data. The data which are obtained in this way may be fairly large or small.

There are two main tasks involved in statistics and they are:

a)      To collect and describe measurement

b)      To make estimation where all measurement are known.

The information which are collected are usually referred as data. A collection of data values forms a data set. Each value in the data set is called a data value or datum. There are different forms of data which is involved in statistics e.g. records of rainfall, patient treated at a health center, arrival and departures at an airport, examination results and so on.

A data may be discrete or continuous. A continuous data may have values like 24.5, 45.03, 87.7, 33.3, etc for example finding the height of students in class.

A discrete data however cannot have values of decimal parts or fractional parts. Only whole numbers are possible. For example the number of patients treated at a health center.

Definition of Some Terms:

Frequency:

Frequency is simply the number of times an item of event occurs or better still a frequency of a class is the number of data values contained in a specific class.

Frequency Distribution:

When observation are made repeated on a variable like marks, height, ages, sizes, weight etc. The outcome is referred to as a frequency distribution. Simply, it is the organization of raw data in table form, using classes and frequencies.

Frequency Distribution (small data):

The data collected in a physics experiment carried out on ten consecutive times in school laboratory. Results collected were as follows 2, 3, 3, 2, 5, 4, 1, 3, 6, 8, 7, and 7. We note that such a data small and can be manipulated easily for the required results.

Frequency Distribution (large data):

The data below gives the masses in kilograms of 50 workers in a manufacturing company

39       30        39        41        77        54        54        45

25       26        20        56        98        46        74        67

71       17        19        58        78        88        78        56

27       87        98        66        76        77        36        36

Frequency Distribution Table:

A frequency distribution is recorded in a frequency distribution table. We consider two types of frequency distribution table; Grouped frequency distribution and Ungrouped frequency distribution table.

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