Another aspect which forms a part of research process is the sampling plant. When the marketing researcher has decided to carry out a field survey, he has to decide whether it is to be a census or sample survey. In almost all the cases, a sample survey undertaken on account of its overwhelming advantages over a census survey.
When a decision in favor of a sample survey has been taken, it is necessary to have a clear definition of the population from which the sample is to be drawn, before deciding on the type of sample design to be used. First, a broad choice is to be made between probability sampling and non-probability sampling. The researcher then selects a specific type of sample design from a number of sample designs. The type of sample design chosen will depend on its suitability and also the availability of the requisite sample frame.
As regards sample size, there are two basic approaches-the ad-hoc or practical approach and the statistical approach. Although the former is widely used in marketing research, it should be the endeavor of the researcher to follow the statistical approach, which is based on well-defined principles. The size of the sample will depend on the degree of the precision required as also on the cost considerations.
The object of sampling is to choose a sample, which will faithfully reproduce the characteristics of the population of universe. In practice, however, this objective is never completely attained on account of the occurrence of the two types of errors-errors due to bias in the selection and sampling errors. It is desirable to minimize these errors and to consult an experienced statistician on sampling.
Organising and Conducting the Field Survey: Till now we have prepared the questionnaires and selected the sample design and size of sample, the next step is to organize and conduct the field survey. Two important aspects should be looked into-interviewing and supervision of fieldwork. The task of interviewing seems to be simple but in reality, it is one of the most difficult tasks in marketing research. This is because respondents are generally hesitant in giving information unless approached with tact, initiative and intelligence. Supervision of fieldwork is equally important to ensure timely and proper completion of the field survey. Neglecting these aspects would result in interviewing errors, which in turn would undermine the utility of the survey.
Processing and Analyzing the Collected Data: Once the field survey is over and questionnaires have been received, the next task is to aggregate the data in a meaningful manner. A number of tables are prepared to bring out the main characteristics of the data. The researcher should have a well thought of framework for processing and analyzing data, and this should be done prior to the collection. It is advisable to prepare dummy tables, as such an exercise would indicate the nature and extent of tabulation as also the comparisons of data that can be undertaken.
In order to derive meaningful results from the statistical table, the researcher may use one or more of the following four steps: The first step is to calculate relevant majors of central tendency as also of dispersion, highlighting the major aspects of the data. The second is to cross tabulate the data to ascertain some useful relationships. The third is to calculate the correlation coefficient and undertake a regression analysis between variables. The fourth is to undertake a multivariate analysis. Such an analysis uses a variety of techniques to determine important relationships amongst several variables.
While designing a research study, the researcher should give adequate thought to the use of particular analytical techniques. In the recent years, many such analytical techniques have proliferated due to the emergence of the computer. The researcher now has access to an increasing assortment of techniques and it is desirable to know well in advance as to what analytical techniques are going to be used, so that the data can be collected accordingly.
It is necessary that the researcher give as much importance to the analysis and interpretation of the data as he has given to their collection. In the absence of proper analysis, data may be rendered useless resulting in a waste of time and money.
