Rai University , May 2015 Ph.D. Coursework of Research Methodology Dr Kishor Bhanushali Associate Professor Unitedworld School of Business Mob: 9898422620 Email: kishorkisu@gmail.com Rai University , May 2015 Ph.D. Coursework of Research Methodology

Sampling Fundamentals

Sampling Sampling may be defined as the selection of some part of an aggregate or totality on the basis of which a judgement or inference about the aggregate or totality is made. In other words, it is the process of obtaining information about an entire population by examining only a part of it.

NEED FOR SAMPLING Save time and money Accurate measurements Only way for infinite population Only choice when a test involves the destruction of the item Sampling usually enables to estimate the sampling errors and, thus, assists in obtaining information concerning some characteristic of the population.

SOME FUNDAMENTAL DEFINITIONS Universe/Population Sampling frame Sampling design Statistics and parameters Sampling error Confidence level and significance level Sampling distribution

IMPORTANT SAMPLING DISTRIBUTIONS Sampling distribution of mean Sampling distribution of proportion Student’s t-distribution F distribution Chi-square distribution

CENTRAL LIMIT THEOREM When sampling is from a normal population, the means of samples drawn from such a population are themselves normally distributed The significance of the central limit theorem lies in the fact that it permits us to use sample statistics to make inferences about population parameters without knowing anything about the shape of the frequency distribution of that population other than what we can get from the sample.

CONCEPT OF STANDARD ERROR The standard deviation of sampling distribution of a statistic is known as its standard error (S.E) and is considered the key to sampling theory.

SAMPLE SIZE AND ITS DETERMINATION Nature of universe Number of classes proposed Nature of study Type of sampling Standard of accuracy and acceptable confidence level Availability of finance Other considerations: (a) Nature of units, (b) size of the population, (c)size of questionnaire, (d) availability of trained investigators, (e)the conditions under which the sample is being conducted, (f) the time available for completion of the study.

Sampling Design

CENSUS AND SAMPLE SURVEY A complete enumeration of all items in the ‘population’ is known as a census inquiry. Highest level of accuracy This type of inquiry involves a great deal of time, money and energy. The respondents selected should be as representative of the total population as possible in order to produce a miniature cross-section. The selected respondents constitute what is technically called a ‘sample’ and the selection process is called ‘sampling technique. Researcher must prepare a sample design for his study i.e., he must plan how a sample should be selected and of what size such a sample would be

STEPS IN SAMPLE DESIGN Type of universe Sampling unit Source list Size of sample Parameters of interest Budgetary constraint Sampling procedure

CRITERIA OF SELECTING A SAMPLING PROCEDURE Inappropriate sampling frame Non-respondents Indeterminancy principle Natural bias in the reporting of data While selecting a sampling procedure, researcher must ensure that the procedure causes a relatively small sampling error and helps to control the systematic bias in a better way.

CHARACTERISTICS OF A GOOD SAMPLE DESIGN (a) Sample design must result in a truly representative sample. (b) Sample design must be such which results in a small sampling error. (c) Sample design must be viable in the context of funds available for the research study. (d) Sample design must be such so that systematic bias can be controlled in a better way. (e) Sample should be such that the results of the sample study can be applied, in general, for the universe with a reasonable level of confidence

DIFFERENT TYPES OF SAMPLE DESIGNS

COMPLEX RANDOM SAMPLING DESIGNS Systematic sampling Stratified sampling Cluster sampling Area sampling Multi-stage sampling Sampling with probability proportional to size Sequential sampling

Methods of Data Collection

The primary data are those which are collected afresh and for the first time, and thus happen to be original in character The secondary data, on the other hand, are those which have already been collected by someone else and which have already been passed through the statistical process

COLLECTION OF PRIMARY DATA (i) observation method, (ii) interview method, (iii) through questionnaires, (iv) through schedules, and (v) other methods which include (a) warranty cards; (b) distributor audits; (c) pantry audits; (d) consumer panels; (e) using mechanical devices; (f) through projective techniques; (g) depth interviews, and (h) content analysis.

Observation Method Most commonly used method specially in studies relating to behavioural sciences Information is sought by way of investigator’s own direct observation without asking from the respondent Subjective bias is eliminated, if observation is done accurately Information obtained under this method relates to what is currently happening Independent of respondents’ willingness to respond Very limited information Structured observation & Unstructured observation Participant observation & non-participant observation controlled & uncontrolled observation.

Personal interview Structured interviews & unstructured interviews Focused interview Clinical interview Non-directive interview Merits & demerits of interview methods Pre-requisites and basic tenets of interviewing

Telephone interviews This method of collecting information consists in contacting respondents on telephone itself. It is not a very widely used method, but plays important part in industrial surveys, particularly in developed regions. Merits & demerits.

COLLECTION OF DATA THROUGH QUESTIONNAIRES Questionnaire is sent (usually by post) to the persons concerned with a request to answer the questions and return the questionnaire The respondents have to answer the questions on their own Pilot Survey Main aspects of a questionnaire :general form, question sequence and question formulation and wording

Essentials of a good questionnaire Short and simple Logical sequence moving from easy to more difficult question Personal and intimate questions should be left to the end. Technical terms and vague expressions capable of different interpretations should be avoided in a questionnaire Open-ended should be avoided Control questions in the questionnaire which indicate the reliability of the respondent Questions affecting the sentiments of respondents should be avoided Adequate space for answers There should always be provision for indications of uncertainty, e.g., “Do not know,” “no preference” and so on Brief directions with regard to filling up the questionnaire should invariably be given in the questionnaire itself Physical appearance

COLLECTION OF DATA THROUGH SCHEDULES schedules (proforma containing a set of questions) are being filled in by the enumerators who are specially appointed for the purpose Enumerators explain the aims and objects of the investigation and also remove the difficulties which any respondent may feel in understanding the implications of a particular question or the definition or concept of difficult terms. Enumerators should be trained

SOME OTHER METHODS OF DATA COLLECTION Warranty cards Distributor or store audits Pantry audits Consumer panels Use of mechanical devices Projective techniques :(i) Word association tests (ii) Sentence completion tests (iii) Story completion tests (iv) Verbal projection tests (v)Pictorial techniques(vi) Play techniques (vii) Quizzes, tests and examinations Depth interviews Content-analysis

COLLECTION OF SECONDARY DATA (a) various publications of the central, state are local governments; (b) various publications of foreign governments or of international bodies and their subsidiary organisations; (c) technical and trade journals; (d) books, magazines and newspapers; (e) reports and publications of various associations connected with business and industry, banks, stock exchanges, etc.; (f) reports prepared by research scholars, universities, economists, etc. in different fields; and (g) public records and statistics, historical documents, and other sources of published information

Characteristics of Secondary Data Reliability of data Suitability of data Adequacy of data

SELECTION OF APPROPRIATE METHOD FOR DATA COLLECTION Nature, scope and object of enquiry Availability of funds Time factor Precision required

Thanks

Unitedworld School of Business Thanks Dr Kishor Bhanushali Associate Professor Unitedworld School of Business Mob: 9898422620 Email: kishorkisu@gmail.com