Experimental Methods in Research

EXPERIMENTAL METHOD

Also called Empirical Research or Cause and Effect Method, it is a data-based

research, coming up with conclusions which are capable of being verified with

observation or experiment.

Experimental research is appropriate when proof is sought that certain variables affect

other variables in some way.

e.g.

-Tenderisers ( independent variable) affect cooking time and texture of meat(

dependent variable) .

– The effect of substituting one ingredient in whole or in part for another such as soya

flour to flour for making high protein bread.

-Develop recipes to use products.

Such research is characterised by the experimenter’s control over the variables under

study and the deliberate manipulation of one of them to study its effects.

In such a research, it is necessary to get at facts first hand, at their source, and actively

go about doing certain things to stimulate the production of desired information.

-Researcher must provide self with a working hypothesis or guess as to the probable

results.

– Then work to get enough facts (data) to prove or disprove the hypothesis.

-He then sets up experimental designs which he thinks will manipulate the persons or

the materials concerned so as to bring forth the desired information.

Evidence gathered through experimental or empirical studies today is considered to be

the most powerful support possible for a given hypothesis.

Lowe,Belle;1958,Experimental Cookery, John Willey & Sons, New York, pp 34-46

DETERMINING SAMPLE DESIGN

Researchers usually draw conclusions about large groups by taking a sample

A Sample is a segment of the population selected to represent the population as a

whole.

Ideally, the sample should be representative and allow the researcher to make accurate

estimates of the thoughts and behaviour of the larger population.Designing the sample calls for three decisions:

Who will be surveyed? ( The Sample)

• The researcher must determine what type of information is needed and who is most

likely to have it.

How many people will be surveyed? (Sample Size)

• Large samples give more reliable results than small samples. However it is not

necessary to sample the entire target population.

How should the sample be chosen? (Sampling)

• Sample members may be chosen at random from the entire population

( probability sample)

• The researcher might select people who are easier to obtain information from

( nonprobability sample)

The needs of the research project will determine which method is most effective

Types of Samples

Probability samples

Simple random sample: Every member of the population has a known and equal

chance of being selected.

Stratified random sample :Population is divided into mutually exclusive groups such

as age groups and randomsamples are drawn from each group.

Cluster(area)sample: The population is divided into mutually exclusive groups such

as blocks, and the researcher draws a sample of the group to interview.

Nonprobability samples

Convenience sample: which to obtain information.

The researcher selects the easiest population members from

Judgment sample: The researcher uses his/her judgement to select population

members who are good prospects for accurate information.

Quota sample: people The researcher finds and interviews a prescribed number of

in each of several categories.

TOOL FOR DATA COLLECTION (RESEARCH INSTRUMENTS)The construction of a research instrument or tool for data collection is the most important asp

of a research project because anything you say by way of findings or conclusions is based upo

the type of information you collect, and the data you collect is entirely dependent upon the

questions that you ask of your respondents. The famous saying about computers- “garbage in

garbage out”- is also applicable for data collection. The research tool provides the input into a

study and therefore the quality and validity of the output (the findings), are solely dependent o

it.

Guidelines to Construct a Research Tool:

The underlying principle behind the guidelines suggested below is to ensure the validity of yo

instrument by making sure that your questions relate to the objectives of your study.

Step I: Clearly define and individually list all the specific objectives or research

Questions for your study.

Step II: For each objective or research questions, list all the associated questions

That you want to answer through your study.

Step III: Take each research question listed in step II and list the information

Required to answer it.

Step IV: Formulate question(s) to obtain this information.

The Questionnaire:

Structured surveys/ interviews employ the use of a questionnaire.

A questionnaire consists of a set of questions presented to a respondent for answers.

The respondents read the questions, interpret what is expected and then write down

the answers themselves.

It is called an Interview Schedule when the researcher asks the questions (and if

necessary, explain them) and record the respondent’s reply on the interview schedule.

Because there are many ways to ask questions, the questionnaire is very flexible.

Questionnaire should be developed and tested carefully before being used on a large

scale.

There are three basic types of questionnaire:

• Closed –ended

• Open-ended

• Combination of both1.Closed –ended Questionnaire:

-Closed ended questions include all possible answers/prewritten response categories,

and respondents are asked to choose among them.

-e.g. multiple choice questions, scale questions

– Type of questions used to generate statistics in quantitative research.

– As these follow a set format, and most responses can be entered easily into a

computer for ease of analysis, greater numbers can be distributed.

2. Open-ended Questionnaire:

-Open-ended questions allow respondents to answer in their own words.

-Questionnaire does not contain boxes to tick but instead leaves a blank section for the respon

to write in an answer.

-Whereas closed –ended questionnaires might be used to find out how many people use a serv

open-ended questionnaires might be used to find out what people think about a service.

-As there are no standard answers to these questions, data analysis is more complex.

– As it is opinions which are sought rather than numbers, fewer questionnaires need to be

distributed.

3. Combination of both:

-This way it is possible to find out how many people use a service and what they think of the

service in the same form.

-Begins with a series of closed –ended questions, with boxes to tick or scales to rank, and then

finish with a section of open-ended questions or more detailed response.

How to construct questionnaires:

• Deciding which questionnaire to use- – closed or open ended,

– self or interviewer administered

• Wording and structure of questions

– Questions should be kept short and simple–avoid double barreled questions in one –ask two Qs rather than one.

– Avoid negative questions-

which have not in them as it is confusing for respondent to agree or disagree.

i.e. two

– Question should not contain Prestige Bias – causing embarrassment or forcing the

respondent to give false answer in order to look good. Questions about educational

qualification or income might elicit this type of response

– Use indirect questions for sensitive issues- in indirect questions respondents can

relate their answer to other people .- Using closed- ended questions- try to make sure that all possible answers are

covered so that respondents are not constrained in their answer. “Don’t Know”

category also needs to be added.

-Avoiding Leading Question: Don’t lead the respondent to answer in a certain way.

e.g. “How often do you wash your car?” assumes that respondent has a car and he

washes his car. Instead, ask a filter question to find if he has a car, and then, ‘If

you wash your car, how many times a year?’

• Length and ordering of the Questions:

– Keep the questionnaire as short as possible

-Ask easy Qs. Which respondents will enjoy answering

– If combined questionnaire, keep open ended Qs for the end.

-Make Qs as interesting as possible and easy to follow by varying type

and length of question

– Group the qs. Into specific topic as this it makes it easier to understand

and follow.

– Layout and spacing is important as cluttered Questionnaire is less likely

to be answered.

Piloting the Questionnaire

Once you have constructed your questionnaire, you must pilot it.

This means that you must test it out to see if it is obtaining the result you require.

This is done by asking people to read it through and see if there are any ambiguities

which you have not noticed.

They should also be asked to comment about the length, structure and wording of the

questionnaire

Alter the questions accordingly

Step 5: COLLECTING DATA :

Having formulated the research problem,, developed a study design, constructed a

research instrument and selected a sample, you then collect the data from which you

will draw inferences and conclusions for your study. Depending upon your plans, you

might commence interviews, mail out a questionnaire, conduct experiments and/or

make observations.Collecting data through any of the methods may involve some ethical issues

in relation to the participants and the researcher :

– Those from whom information is collected or those who are studied by a

researcher become participants of the study.