Sam Paling

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SAMPALING

Research Methodology


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You have to first know what you are looking for -this is not always so easy.

If your new chocolate bar isnt selling well, youdont automatically do market research on thetaste - because maybe the reason has to do

with the packaging.

Problem Definition


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hypothesis

After the problem has been defined;(Step 1), and an exploratory

investigation (Step 2), has beenconducted, it is possible to thenformulate a Hypothesis (Step 3)


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A tentative explanation about therelationship between variables as a startingpoint for further testing .

The way of thinking about how somethingworks - and using your original guess as astarting point for further investigation

Hypothesis


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The selection of areas considered reasonably typicalof the total market, and introducing a new product tothese areas with a total marketing campaign todetermine consumer response before marketing theproduct nationally.

Test Marketing


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What is a sample ?

A subset of some of the units in the populationA subgroup of the population


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Example

population size = 1000 ( blue collar)

Sample size = 200

(chosen for studying performance of blue collar)


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Why sampling ?

Too expensive to test the entire populationImpossible to test entire population

Testing the entire population often produceserrorsMay give accurate results

Enables to researchers to make estimates of some unknown characteristics of population inquestion

High scope of accuracy and reliability


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Sampling Methods

Probability Non-Probability

Based on probability theory. Focus on volunteers, easily

available units, or those that justhappen to be present when theresearch is done.

Every unit of the population of

interest must be identified, andall units must have a known,non-zero chance of beingselected into the sample.

Useful for quick and cheap

studies, for case studies, forqualitative research, for pilotstudies, and for developinghypotheses for future research.


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Probability

Simple random sample

Systematic random sampling

Stratified random samplingCluster sampling


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Simple random sampling

Population = nSample = nAll possible sample= n

A random number table is a list of numbers, composedof the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. Numbers in thelist are arranged so that each digit has no predictablerelationship to the digits that preceded it or to the digitsthat followed it. In short, the digits are arrangedrandomly. The numbers in a random number table arerandom numbersLink - http://stattrek.com/Tables/Random.aspx


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Simple random sampling

25 Random Numbers068 057 036 098 014 015 012 022 094 080094 052 077 076 006 013 018 002 051 080066 035 000 004 044

* This table of 25 random numbers was produced according to the followingspecifications: Numbers were randomly selected from within the range of 0 to 100.Duplicate numbers were allowed.


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Systematic Random sampling

most appropriate practical method forsampling

for instance - to select every X th item fromthe list.


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Systematic Random sampling

There is a population of 2000 and sample size is 100. apply thesystematic random sampling.

Identify Population size = NSample size = n= 100Interval =k=?

k= N/n = 2000/100 = 20

Now Select a random number x between 1 and k.

Suppose first x th number is 12Then next number is = x+k = 12+20 = 32 so on


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Question

Population of people going to night-clubs is onan average about 250-300 people in a city.Number of night clubs are 30.

A researcher wants to select people forinterview among this population .Applysystematic random sampling to identify thepeople.


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Stratified sampling

Constructed by classifying the population in sub-populations (or strata), base on some well-known characteristics of the population, such asage, gender or socio-economic status.

The selection of elements is then madeseparately from within each strata, usually byrandom or systematic sampling methods.


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Example

Sample size = n = 30

Population size =N= 8000

Population is divided into three strata ;

N1= 4000 , N 2= 2400 , N 3= 1600

Find the sample sizes for the different strata by using proportional allocation : For Proportional Allocation

P1 = 30 (4000/8000) = 15

P2 and P 3 = ??


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Question

In the class 12 th , pupils are offered Maths,Physics or Chemistry homework. 28 chooseMaths homework 47 choose Physicshomework 25 choose Chemistry homework. If you wanted to check the homework of any 20students, how many of each would you

choose? ..


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Cluster

Suitable for conducting research studies thatcover large geographic area.

Once the cluster is formed the researcher caneither go for one stage, two stages, or multistage cluster sampling.


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Example

Suppose that the Department of Agriculture wishesto investigate the use of pesticides by farmers inEngland.

A cluster sample could be taken by identifying thedifferent counties in England as clusters. A sample of these counties (clusters) would then bechosen at random, so all farmers in those countiesselected would be included in the sample. It iseasier to visit several farmers in the same countythan it is to travel to each farm in a random sampleto observe the use of pesticides.


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Non-Probability

Convenience sample Purposive sample Quota sample


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Convenience

An exploratory research where the researcheris interested in getting an inexpensiveapproximation of the truth. As the nameimplies, the sample is selected because theyare convenient.


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Purposive

The researcher selects the units with somepurpose in mind, for example, students wholive in dorms on campus, or experts on urbandevelopment.


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Quota

widely used in opinion polling and marketresearch.Interviewers are each given a quota of subjectsof specified type to attempt to recruit forexample, an interviewer might be told to go outand select 20 adult men and 20 adult women,

10 teenage girls and 10 teenage boys so thatthey could interview them about their televisionviewing.


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Differences between ProbabilitySampling and Non-Probability

Probability (Random) Sampling Non-Probability (Non-Random)Sampling

Allows use of statistics, testshypotheses

Exploratory research, generateshypotheses

Can estimate populationparameters

Population parameters are not of interest

Eliminates bias Adequacy of the sample can't beknown

Must have random selection of units

Cheaper, easier, quicker to carryout


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Steps in Sampling Design

Type of universe: The universe can be finite orinfinite. In finite universe the number of items iscertain, but in case of an infinite universe (citypopulation, factory workers etc,) the number of items is infinite, i.e., we cannot have any ideaabout the total number of items ( number of stars).Sampling Unit: Sampling Unit may be geographicalone such as state, district, village, etc., or aconstruction unit such as house flat., it may beindividual.

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Steps in Sampling Design (contd..)

Source list : It is also known as samplingframe from which sample is to be drawn. Itcontains the names of all items of a universe

(incase of finite universe only). If the sourcelist is not available, the researcher has toprepare it. Such list should be comprehensive,correct, reliable and appropriate. It isextremely important for the source list to beas representative of the population aspossible.

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Size of sample : The sample size should neither beexcessively large, nor too small. It should be optimum.An optimum sample is one which fulfills the

requirements of efficiency, appropriate representation,reliability and flexibility. While deciding the sample size,researcher must determine the desired precision as alsoan acceptable confidence level for the estimate.


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Parameters of interest: In determining the sampledesign, one must consider the question of thespecific population parameters which are of interest. For instance, we may be interested inestimating the proportion of persons with somecharacteristic in the population, or we may be

interested in knowing some average or the othermeasure concerning the population.

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Sampling procedure: Finally, the researchermust decide the type of sample he will use

i.e., he must decide about the technique to beused in selecting the items for the sample. Infact, this technique or procedure stands forthe sample design itself. There are severalsample design out of which the researchermust choose one for his study.

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Definition

A set of routine procedures to continuously collect,monitor, and present internal and externalinformation on company performance andopportunities in the marketplace.

Marketing Information Systems


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For some companies, market knowledge comes in on a regularbasis.

Some stuff is Data, and some is Information

Data = statistics, opinions in surveys, facts, predictions etc.

Information = data RELEVANT to the Marketing Manager inmaking decisions



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All of this depends on the ability of thecompany to use technology to help it be

better than the competition



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THANK YOU

Sam Paling

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