New Terms Flashcards
Snowball Sampling
Participants recruit others; + access difficult to locate groups; - not a good cross-section of population.
Online Experiments
assess participants via internet/social media; + assess large groups, cost effective, diverse, quicker analysis; - difficult to deal with ethical issues, limited methods used.
Systematic Sampling
Every nth number of the population; + no researcher bias; - may not be representative.
Inter-rater Reliability
Extent to which 2 observers agree. General rule is that if there is 80% agreement, then there is inter-observer reliability.
Test-retest Reliability
Assess external reliability. Participants do test, then sometime later when they have forgotten, they do the test again and the responses are compared.
Split-half Reliability
Assess internal reliability. Participants are given a test, the responses are split and compared.
Concurrent Validity
Way of establishing external validity by comparing an existing test or questionnaire to one you are interested in.
Predictive Validity
Correlating the results of the test with some other examples of the behaviour that is being tested.
Face Validity
A form of external validity - the extent to which test items look like what the test claims to measure.
Content Validity
Aims to show that the content , like questions on the test, represent the area of interest (internal validity).
Construct Validity
The extent to which performance on the test measures an identified underlying construct (internal validity).
Frequency Table
Used to display raw data that Is easy to understand and interpret.
Bar Charts
Used with interval and ratio data. Used to display data or information that changes continuously over time and allow us to see overall trends such as an increase or decrease in data over time.
Histograms
Use continuous rather than discrete data in a bar chart. The variable in the horizontal is a scale of something such as length or mass. used with interval data.
Pie Charts
Shows differences in frequencies and percentages amongst categories of a nominal or ordinal data.
Scatter Diagrams
Used to display data when study is correlational.
EEG
Electrodes placed on scalp and electrical activity in different areas can be recorded.
E.g. Dement Kleitman - detected different stages of sleep.
CAT
Takes a series of x-rays to for 2 or 3 dimensional pictures. Usually a dye is injected as a contrast and the patient is place in the CAT machine.
MRI
Use of magnetic field that causes the brain to emit radio waves, a detector reads these and uses them to map the structure of the brain.
PET
Slightly radioactive glucose given to patient. Most active parts of the brain use glucose and radiation detectors “see” this area, building up a picture of activity in the brain.
Longitudinal Studies
Research conducted over long periods of time to observe long term effects. Case studies are often longitudinal. Often used by developmental psychologists.
Cross-sectional Studies
One group of a younger age are compared to another groups of an older age at the same point in time to investigate effects of age on behaviour.
Normal Distributions
Classic bell shaped curve.
Features: mean, median, mode in exact mid point.
Distribution symmetrical at mid point.
Dispersion of scores either side of the mid point is consistent and can be expressed in standard deviation.
Left Skew/Negative
Some population scores are distributed equally around the mean.
E.g. Easy test - mostly high scores - negative skew.
