Collection of data Classification of data Observation and

Ø Collection of data, Classification of data, Observation and Variable

Collection of Statistical Data: Statistical Data A sequence of observations, made on a set of objects included in the sample drawn from population, is known as statistical data.

(1) Ungrouped Data which have been arranged in a systematic order are called raw data or ungrouped data. (2) Grouped Data presented in the form of a frequency distribution are called grouped data. Collection of Data The first step in any enquiry (investigation) is the collection of data. The data may be collected for the whole population or for a sample only. It is mostly collected on a sample basis. Collecting data is very difficult job. The enumerator or investigator is the well trained individual who collects the statistical data. The respondents are the persons from whom the information is collected.

Types of Data There are two types (sources) for the collection of data: (1) Primary Data (2) Secondary Data

(1) Primary Data Primary data are the first hand information which is collected, compiled and published by organizations for some purpose. They are the most original data in character and have not undergone any sort of statistical treatment. Example: Population census reports are primary data because these are collected, complied and published by the population census organization. (2) Secondary Data The secondary data are the second hand information which is already collected by an organization for some purpose and are available for the present study. Secondary data are not pure in character and have undergone some treatment at least once. Example: An economic survey of England is secondary data because the data are collected by more than one organization like the Bureau of Statistics, Board of Revenue, banks, etc.

Methods of Collecting Primary Data Primary data are collected using the following methods: 1. Personal Investigation: The researcher conducts the survey him/herself and collects data from it. The data collected in this way are usually accurate and reliable. This method of collecting data is only applicable in case of small research projects. 2. Through Investigation: Trained investigators are employed to collect the data. These investigators contact the individuals and fill in questionnaires after asking for the required information. Most organizations utilize this method.

3. Collection Through Questionnaire: Researchers get the data from local representations or agents that are based upon their own experience. This method is quick but gives only a rough estimate. 4. Through the Telephone: Researchers get information from individuals through the telephone. This method is quick and gives accurate information.

Methods of Collecting Secondary Data Secondary data are collected by the following methods: 1. Official: e. g. publications from the Statistical Division, Ministry of Finance, the Federal Bureaus of Statistics, Ministries of Food, Agriculture, Industry, Labor, etc. 2. Semi-Official: e. g. State Bank, Railway Board, Central Cotton Committee, Boards of Economic Enquiry, etc. 3. Publication of Trade Associations, Chambers of Commerce, etc. 4. Technical and Trade Journals and Newspapers.

Classification of Data: The process of arranging data into homogenous groups or classes according to some common characteristics present in the data is called classification. For example: During the process of sorting letters in a post office, the letters are classified according to the cities and further arranged according to streets

Bases of Classification There are four important bases of classification: (1) Qualitative Base (2) Quantitative Base (3) Geographical Base (4) Chronological or Temporal Base (1) Qualitative Base When the data are classified according to a quality or attribute such as sex, religion, literacy, intelligence, etc.

(1) Qualitative Base When the data are classified according to a quality or attribute such as sex, religion, literacy, intelligence, etc. (2) Quantitative Base When the data are classified by quantitative characteristics like height, weight, age, income, etc. (3) Geographical Base When the data are classified by geographical regions or location, like states, provinces, cities, countries, etc. (4) Chronological or Temporal Base When the data are classified or arranged by their time of occurrence, such as years, months, weeks, days, etc. For example: Time series data.

Types of Classification (1) One -way Classification If we classify observed data keeping in view a single characteristic, this type of classification is known as one-way classification. For example: The population of the world may be classified by religion as Muslim, Christian, etc.

(2) Two -way Classification If we consider two characteristics at a time in order to classify the observed data then we are doing two way classification. For example: The population of the world may be classified by religion and sex. (3) Multi -way Classification We may consider more than two characteristics at a time to classify given or observed data. In this way we deal in multi-way classification. For example: The population of the world may be classified by religion, sex and literacy.

Observation Definition: General Meaning of Observation in Statistics. An observation in statistics is a value of something of interest you’re measuring or counting during a study or experiment: a person’s height, a bank account value at a certain point in time, or number of animals. Variables: A characteristics which varies by individual to individual or an object to object is called as variables. For example age varies person to person. 1 -Qualitative Variables 2 -Quantative Variables

Quantitative Variable: A variable is called a Quantitative variable when a characteristics can be expressed in numerical form such as age, weight, income, number of students, number of children etc… Qualitative Variable: When characteristics cant be expressed numerically such as education, gender, eye color, education, satisfaction level, intelligence The number of family members Amount of money spent of books, length of phone call recorded at switch bowl. Continuous Variable:

Continuous Variable: If it can take any fractional numbers, within a given interval. A set of observations on a continuous variable is called continuous data. Discrete Variable: It goes like 2, 3, 4, 5…. IT GOES IN SEQUENCE. . It is one that can take only a discrete set or integer and whole numbers. A discrete variable represents count data such as number of students in class room. Number of persons in a family the number of toms in a house , the number of deaths. A set of observations of discrete variables is called discrete data. Number of goals scored in a hockey match is discreet Temperature at a certain place is continuous. The number of children in a family is discrete