Market Research 3

What is a sample?

A subset of a given population (e.g., all vegetarians living in Austria).

What are the main benefits of sampling?

Lower cost, less time investment, higher potential accuracy, and control of the interactive testing effect.

Define "Population" in research.

The set of all objects that possess a common set of characteristics relevant to the research problem.

What is a Sampling Frame?

A list of all sampling units available for selection from which the actual sample is drawn.

What are the 6 steps in the Sampling Process?

1. Define population,

2. Specify frame,

3. Select method,

4. Determine size,

5. Select elements,

6. Collect data.

How is a population defined in Step 1?

In terms of elements (who), units (where they are found), extent (geographic area), and time.

What defines Probability Sampling?

An objective method where every element has a known, non-zero chance of being selected.

types: stratified, clustered, systematic random, simple random

What defines Non-probability Sampling?

A subjective method where selection relies on personal judgment rather than chance.

types: snowball, convenience, judgement, quota, purposive

What is Convenience Sampling?

Selecting cases based on ease of access

What is Judgment Sampling?

A non-probability technique where the researcher selects samples based on expert knowledge.

How does Quota Sampling work?

The population is divided into cells based on characteristics, and a convenience sample is taken until each cell quota is met.

What is Snowball Sampling?

Starting with a key contact who refers others, creating a chain

Define Simple Random Sampling (SRS).

The purest probability method where every element has an equal chance of selection, often using random numbers.

types: with or without replacement

What is Stratified Sampling?

Dividing the population into mutually exclusive groups (strata) and taking a random sample from each.

What is Cluster Sampling?

Dividing the population into groups (clusters) and randomly selecting entire clusters to study.

What is Systematic Sampling?

Selecting every kth element from a list after a random starting point.

What factors determine Sample Size?

Required precision,

population nature,

budget,

time,

and resources.

What is a "homogeneous" population? What are the implications for sample size?

A population where units cannot be easily distinguished by auxiliary information.

What is Sampling Error?

Inaccuracy caused by studying a sample instead of the whole population - difference btw sample and pop.

Non-sampling error

errors that occur in the research process

types: sampling frame & non-response error

Non-response Error?

Failure to get data from selected elements because they couldn't be reached or refused to participate.

Sampling Frame ?

Failure to include all relevant elements or sections of the target population in the list.

How can you remedy Sampling Error?

By increasing the sample size or using a more statistically efficient sampling method.

Avoiding non-sampling error

• improve coverage

• improve response rate

• improve response quality

Issues with international sample selection

• population lists often unavailable

• insufficient knowledge of population characteristics

• uneven service

• reduce expertise

solution

• probability samples combined with judgement and convenience samples