chapter 7 b samplingmethods 120827123446 phpapp02

8/13/2019 Chapter 7 B Samplingmethods 120827123446 Phpapp02

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SAMPLINGMETHODS


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Sample vs. Population

Population

Sample


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What do qualitative

researchers worry about?

I want to seethe world

through theeyes of myrespondents.

I want todescribe the

context in alot of detail.

I want to showhow socialchangeoccurs. Iminterested inhow thingscome to be.

I really wantmy researchapproach to

be flexibleand able tochange.


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Social actors are notpredictable likeobjects.

Randomized events areirrelevant to social life.

Probability sampling is

expensive and inefficient.

Non-probability sampling isthe best approach.


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Types of samples

Sampling method

Probabilitic Non- Probabilitic

1. Simple Random Sample2. Systematic Random Sample3. Stratified Random Sample4. Cluster sample5. Multi Cluster Sample

Without Replacement

With Replacement1. Judgmental

sampling2. Quota

Sampling3. Snow ball

Sampling


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Simple Random Sample

Get a list or sampling frame

a. This is the hard part! It must not systematically excludeanyone.

Generate random numbers

Select one person per random numbers


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Systematic Random Sample

Select a random number, which will be knownas k

Get a list of people, or observe a flow of people(e.g., pedestrians on a corner)

Select every kth person

Careful that there is no systematic rhythm to theflow or list of people.

If every 4thperson on the list is, say, rich or senioror some other consistent pattern, avoid this method


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Stratified Random Sample

1. Separate your population into groups orstrata

2. Do either a simple random sample orsystematic random sample from there

a. Note you must know easily what the

strata are before attempting this

b. If your sampling frame is sorted by, say,school district, then youre able to usethis method


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Multi-stage Cluster Sample

Get a list of clusters, e.g., branches of acompany

Randomly sample clusters from that list

Have a list of, say, 10 branches

Randomly sample people within thosebranches

This method is complex and expensive


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The Convenience Sample

Find some people that are easy to find


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The Snowball Sample

Find a few people that are relevant toyour topic.

Ask them to refer you to more of them.


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The Quota Sample

Determine what the population looks like in termsof specific qualities.

Create quotas based on those qualities.

Select people for each quota.


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The Theoretical Sample


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Accidental sampling

A type of nonprobability sampling whichinvolves the sample being drawn from thatpart of the population which is close to hand

The researcher using such a sample cannotscientifically make generalizations about thetotal population

In social science research, snowballsampling is a similar technique


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Panel sampling

The method of first selecting a group ofparticipants through a random sampling

Period of data collection is called a"wave

Panel sampling can also be used toinform researchers about within-personhealth changes due to age


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How many?

Qualitative researchers seek saturation

How many isnt the issue. Do you understandthe phenomenon? Have you learned enough?

Mere numbers are irrelevant. You wantverstehn or deep understanding

Quantitative researchers seek statistical

validity Can you safely generalize to the population?

Have you systematically excluded anyone?(See the famous sampling mistake)


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Improving Response Rates

Personalize the invitation

Offer money -- no strings attached


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Thank

You all

chapter 7 b samplingmethods 120827123446 phpapp02

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