Statistics: is the study that deals with methods of collecting, analyzing, interpreting and presenting the empirical data.
Statistical Methods are used for analyzing data and drawing valid inferences or intelligent judgments.
Applications of Statistics:
Statistics methods are used in fields such as:
8. Marketing etc
Data are the raw facts and figures such as numbers, words, measurements, observations or just descriptions of things. Data can be qualitative or quantitative.
Types of Data:
1. Qualitative data is a descriptive information (it describes something).E.g.: Departments in college (e.g. IT, Biotech, English), Types of pets owned (e.g. dog, cat, fish).
2. Quantitative data is a numerical information (numbers).Quantitative data can be further classified as discrete and continuous.
(i)Discrete data are countable fixed value. E.g.: Number of books owned (e.g. 1, 2, 4), Bank account balance (e.g. 1000, 500).
(ii)Continuous data are range of data which is not fixed. E.g.: Height, weight, temperature and length etc, Number of stars in a galaxy, speed.
Collection of data:
The first step in the statistical investigation is collection of data.
The data originally collected by the investigator for the purpose of study is called primary data. These data may be collected by:
(i) Carrying out an Experiment
(ii) Interviewing a selected individuals
(iii) Preparing Questionnaires etc.
The data obtained from materials available in published record such as journals, thesis etc are called secondary data .E.g.: Censuses, information collected by government departments, organizational record etc.
Population vs. Sample:
The population includes all of the elements from the data set whereas the sample is only a portion (one or more observation) of the population.