Week 5

Determining sample size: Things that must be considered:

Research objective Degree of accuracy Resources Time frame Knowledge of the target population Scope of the research Statistical Analysis needed

Sampling frame

The list of all eligible sampling units.

Two tasks of Measurement Process

The measurement process consists of two tasks: construct selection/development and scale measurement.

Population

an identifiable group of elements (for example, people, products, organizations) of interest to the researcher and pertinent to the information problem.

In order to conclude a cause-effect relationship

Researchers must establish that there is temporal order between the variables. There must be a meaningful association between the variables. Researchers must account for (or control for) all other possible variables other than the alleged cause!

For example, the variables listed below were used to measure the concept of "customer interaction:

This customer was easy to talk with. This customer genuinely enjoyed my helping her/him. This customer likes to talk to people. This customer was interested in socializing. This customer was friendly. This customer tried to establish a personal relationship. This customer seemed interested in me, not only as a salesperson, but also as a person.

What is A construct?

A construct is an abstract idea or concept formed in a person's mind. This idea is a combination of a number of similar characteristics of the construct. The characteristics are the variables that collectively define the concept and make measurement of the concept possible.

Census:

A research study that includes data about every member of the defined target population.

Rule of Thumb for Construct Development

A rule of thumb is that if an object's features can be directly measured using physical characteristics, then that feature is a concrete variable and not an abstract construct. Abstract constructs are not physical characteristics and are measured indirectly.

Steps in developing a sampling plan

A sampling plan is the blueprint to ensure the data collected are representative of the population. A good sampling plan includes the following steps: (1) define the target population, (2) select the data collection method, (3) identify the sampling frames needed, (4) select the appropriate sampling method, (5) determine necessary sample sizes and overall contact rates, (6) create an operating plan for selecting sampling units, and (7) execute the operational plan.

What is Causal research?

A type of conclusive research where the major objective is to obtain evidence regarding cause-and-effect (causal) relationships. Marketing managers continually make decisions based on assumed causal relationships. These assumptions may not be justifiable, and the validity of the causal relationships should be examined via formal research.

Disadvantages of Snowball Sampling

But snowball sampling allows bias to enter the study. If there are significant differences between people who are known in certain social circles and those who are not, there may be problems with this sampling technique.

What is construct development?

Construct development begins with an accurate definition of the purpose of the study and the research problem. Without a clear initial understanding of the research problem, the researcher is likely to collect irrelevant or inaccurate data, thereby wasting a great deal of time, effort, and money. Construct development is the process in which researchers identify characteristics that define the concept being studied by the researcher. Once the characteristics are identified, the researcher must then develop a method of indirectly measuring the concept. Each construct may have abstract and concrete properties.

Advantages of Convenience Sampling

Convenience sampling enables a large number of respondents to be interviewed in a relatively short time.

Simple random sampling

Every sampling unit has a known and equal chance of being selected! For example, an instructor could draw a sample of 10 students from among 30 students in a marketing research class. The instructor could write each student's name on a separate, identical piece of paper and place all of the names in a hat. Each student would have an equal, known probability of selection.

disadvantages

If the judgment is not correct, it will be a waste of time and money.

Advantages for Judgement Sampling

If the judgment of the researcher is correct, the sample generated by judgment sampling will be better than one generated by convenience sampling.

Judgment (purposive) sampling

In judgment sampling, sometimes referred to as purposive sampling, respondents are selected because the researcher believes they meet the requirements of the study. For example, sales representatives may be interviewed rather than customers to determine whether customers' wants and needs are changing or to assess the firm's product or service performance.

Measurement

Is the process of developing methods to systematically characterize or quantify information about persons, events, ideas, or objects of interest. As part of the measurement process, researchers assign either numbers or labels to phenomena they measure. For example, when gathering data about consumers who shop for automobiles online, a researcher may collect information about their attitudes, perceptions, past online purchase behaviors, and demographic characteristics. Then, numbers are used to represent how individuals responded to questions in each of these areas.

Sampling:

Selection of a small number of elements from a larger defined target group of elements and expecting that the information gathered from the small group will allow judgments to be made about the larger group.

Advantages Snowball Sampling

Snowball sampling is a reasonable method of identifying respondents who are members of small, hard-to-reach, uniquely defined target populations. As a nonprobability sampling method, it is most useful in qualitative research.

disadvantages

The primary disadvantage of simple random sampling is the difficulty of obtaining a complete and accurate listing of the target population elements. Simple random sampling requires that all sampling units be identified. For this reason, simple random sampling works best for small populations where accurate lists are available.

What is the primary focus for casual research? What is the difference between Causal Research and Exploratory?

The primary focus of causal research is to obtain data that enables researchers to assess "cause- effect" relationships between two or more variables. In contrast, data from exploratory and survey research designs enables researchers to assess non-causal relationships between variables. In exploratory and survey research designs, initial research questions are typically framed broadly and hypotheses focus on the magnitude and/or direction of the association, and not on causality. In contrast, questions examining causal relationships between variables are framed with the focus being on the specific impact (or influence) one variable causes on another variable.

Advantages

The technique is easily understood and the survey's results can be generalized to the defined target population with a pre-specified margin of error. Another advantage is that simple random samples produce unbiased estimates of the population's characteristics.

Disadvantages of Convenience Sampling

Using convenience samples to develop constructs and scales can be risky. Another major disadvantage of convenience samples is that the data are not generalizable to the defined target population.

Convenience Sampling

a method in which samples are drawn based on convenience. For example, interviewing individuals at shopping malls or other high-traffic areas is a common method of generating a convenience sample.

Defined target population

consists of the complete group of elements (people or objects) that are identified for investigation based on the objectives of the research project.

Snowball sampling

involves identifying a set of respondents who can help the researcher identify additional people to include in the study. This method of sampling is also called referral sampling, because one respondent refers other potential respondents. Snowball sampling typically is used in situations where (1) the defined target population is small and unique, and (2) compiling a complete list of sampling units is very difficult.

Stratified random sampling

involves the separation of the target population into different groups, called strata, and the selection of samples from each stratum. Stratified random sampling is similar to segmentation of the defined target population into smaller, more homogeneous sets of elements.