Unit 1///2 Flashcards
What is bivariate data
Involves pairs of related data
How can you avoid bias
Taking into account characteristics of whole population
What are sampling units
All People or items that are to be sampled
What does replicating and repeating an experiment likely to give
Valid and reliable results
What are extraneous variables
Any variables that you are not interested in but that could affect the results of your experiment
What is a hypothesis
An idea that can be tested by collecting and analysing data
What do you need to consider when designing investigations
Time
Cost
Ethical issues
What is judgement sampling
Using your judgement to select a sample eg asking people you think will be suitable
What is opportunity sampling
Using the people or objects available at the time to select a sample
What is cluster sampling
Used when data naturally splits into groups
What is quota sampling
Group the population by characteristics and use a pre determined number
What is stratified sampling
When the total population is divided into groups
How to work out stratified sample
Sample size/population size x stratum size
What is random sampling
Where every member of a population has an equal chance of being chosen
What is a questionnaire
A set of questions designed to obtain data
How to work out capture recapture
Do practice questions
What does a questionnaire need
Neutral survey questions
Avoid biased questions
Keep questions short
What is systematic sampling
Collecting data in an ordered or regular way eg every fifth Person
What is a control group
is used to establish a cause-and-effect relationship by isolating the effect of an independent variable.
What are the 3 types of experiments
Laboratory
Field
Natural
What is a natural experiment
Experiments carried out in test subjects everyday environement
What is a laboratory experiment
Experiments conducted in a controlled environment
Give an advantage of Laboratory experiments
Easy to replicate
Control extraneous variables
Give a disadvantage of a lab experiment
Test subject may behave differently
Give an advantage of field and natural experiments
More likely to reflect real life behaviour
What is an explanatory variable
What you change (independent)
