Week 3 Flashcards
External validity
Can results generalise to wider population.
Quasi experiment
Non random assignment of participants. I.e. Different professions, age etc
Ecological validity
Wether the experiment actually mirrors the real life conditions of phenom men being measured.
Measurement error
Assumed discrepancy of data collected and true value of measurement
Validity
Measuring what we set out to measure. Must be reliable too
Reliability
Consistency of results. Does not have to be valid. Must measure in same way each time.
Face validity
Weak type of validity. What the test taker thinks of the test. I.e personality test with weird questions.
Content validity
Are the items a representative sample of all possible items. Ie test measuring only week 1/2 of 10 weeks.
Criterion-related validity
Extent to which a score indicates a level if performance on an criterion against which it is compared. Predictive/concurrent.
I.e. GPa and honours entry
Construct validity
Intelligence measurement and how do we know they are measuring intelligence as a construct.
Convergent validity (construct validity)
Should correlate with questionnaires that measure
Same construct
Related constructs
Discriminant validity
Should not correlate with questionnaires that measure
Different constructs
Unrelated constructs
Experimenter effect (reactivity of measures)
What happens when bias of experimenter is known and impacts subjects performance. Hawthorne experiment with lights.
Reliability 3 types
Test-retest
Internal consistency
Interrater reliability
Test-retest
Measure same individuals at two points in time
Internal consistency
Uses responses at only one time and focuses on consistency of items (all measuring same things?)
Interrater reliability
Evidence of reliability when multiple taters agree in observations of the same thing
Operationally defined variables
Must be defined how going to capture/measure the variable each time. To turn it into numbers…
Levels of measurement
Relationship between what is being measured and the numbers that represent what is being measured.
Categorical variable
Names distinct entities I.e. Binary (2 groups)
Continuous variables
Can take on any value on the measurement scale
4 levels of measurement:
Nominal
Ordinal
Interval
Ratio
Nominal variable
Two or more things are equivalent in some way are given same number. Numbers have no meaning…just used as labels (categorical)
Linear model
Based on a straight line
Variables
Measured constructs that vary across entities in the sample
Parameters
Estimated from the data usually constants representing fundamental truth about the relations between variables I.e. Mean median
Coefficients (b)
Estimate relationship btwn 2 variables
Sum of squares
Same process as sum of squares except deviance = outcome - model (asseses fit) total deviance of scores from the mean
Sum of squares as a good measurement
Relies on amount of data
More data points
Higher SS