Sampling techniques and experimental designs Flashcards
What is the difference between population and sample?
In an experiment where 3 people of a class are tested, the class would be the population and the sample would be the 3 people being studied.
Random sampling is when…
researchers make sure that every member of the target population has an equal chancee of getting invited.
Opportunity. or convenience sampling:
using a group of participants just because they are available (psych students)
Stratified sampling is when…
a sample that considers the diversity of the target opinion. (Has to maintain the same proportion)
Snowball sample is when..
participants invite other people they know to participate
Purposive sampling:
a non-probability sample where you are selected based on the characteristics of a population.
Self-selected sampling:
participants volunteer to participate.
Independent measures designs allocate participants in X groups
2
Independent measures designs are based on:
the placement of a sample in two groups (control or experimental), manipulating their conditions except IV until they are equal, and comparing their DV.
Matched pair design organises groups in the following form:
Matching is used to make groups, researchers rank participants to control participants in terms of traits abilities and capabilities.
Repeated measure designs is used on experiments with the goal to…
compare conditions rather than participants.
On repeated measure designs the same group of participants is exposed to…
Two or more conditions, and their results are compared.
Practice and Fatigue are order effects that can appear on repeated measures designs, describe them.
Practice: participants improve by getting used to trials
Fatigue: participants get tired of trials and their performance decreases.
Counterbalancing on repeated measures design is when…
When more that two groups are used, to invert the order of the conditions and compare them.
