Data Management

Sample

The portion of a population who will be surveyed

Population

All the individuals who belong to a group being studied

Discrete data

Can be described using whole numbers

Continuous data

Only measurable with real numbers

Qualitative data

Cannot be measured numerically (categorical)

Quanitative data

Can be measured numerically

Simple random

Randomly choose a sample from the population

Systematic random

Start from one person and then go to every blank person after that

Stratified random

Split the population into groups and then pick a percentage of people from each group. ex: 10% from every group

Cluster random

Split the population into groups and pick a few groups

Multi-stage random

Split the population into groups and then randomly pick a sample from each group

Voluntary response

Tell the population about the survey and those who want to participate will.

Convenience

Taking a sample of people close to you.

Bias

Any factor that favours certain outcomes or responses and skews the results of a survey.

Sampling bias

When the chosen sample does not reflect the population

Non-response bias

When particular groups are underrepresented because they did not participate.

Response bias

Leading questions or sensitive and embarrassing questions in a survey.

Measurement bias

When the collection method affects the results

Open, closed, information, checklist, rating and ranking.

What are the 6 types of questions used in a typical survey?