3001 2-2 Flashcards
Nominal
This is the most basic level of measurement, where data is categorized without any quantitative value or order. Categories are distinct and mutually exclusive.
Example: Gender, race, or types of therapy
ratio
The highest level of measurement includes equal intervals and a true zero point.
Example: Height, weight, reaction time, income, or the number of therapy sessions attended.
ordinal
This scale involves ordered categories, but the intervals between them are not necessarily equal. It provides rank-order information but does not measure the precise differences between ranks.
Example: Levels of agreement on a survey, education level, or rankings in a competition.
Interval
This scale has equal intervals between values, but it lacks a true zero point.
Examples: IQ scores, temperature in Celsius or Fahrenheit, or standardized test scores.
Choosing a scale of measurement
Scales differ in amount of information:
Nominal: difference in quality
Ordinal: crude information about quantity
Interval: also tells us how much scores differ
Ratio: tells us how much of the quality is/was present
Are any “psychological variables” measured on an interval or ratio scale?
Psychology = study of behavior
Psychological variable = measure of behavior
The psychological variable measured on a ratio scale of measurement: reaction time
Reliability
repeatability or consistency of a
measurement
Extent to which the measurement reflects the true value of what you are measuring
2 components of a measurement
- True score
- Measurement error
ways to assess reliability
test-retest reliability
alternate forms reliability/Parallel forms reliability
internal consistency reliability
interrater-interobserver reliability
test-retest reliability
Administer the same test at two different times
Compute correlation between 1st and 2nd scores
alternate forms reliability/Parallel forms reliability
Tests the equivalence between two different forms of the same test (e.g., memory tests)
administer both forms to many people
Compute the correlation between scores on the two tests
internal consistency reliability
Split-half reliability
- Compute scores for two halves of the test
- Compute correlation between scores
on two halves of tes
Interrater/interobserver reliability
Multiple observers rate many observations
- Compute the correlation between ratings
Constructs
an idea developed to permit the categorization and description of some directly observable behavior
Psychological constructs are not directly
observable
Must be operationally defined
construct validity
Is our measurement, as operationally defined, really measuring what we think it is measuring?
Face Validity
refers to the extent to which a test or measurement appears to measure what it is intended to measure based on a superficial or subjective judgment.
Relationship between reliability and validity
A measurement can be consistent (reliable) but still incorrect (not valid). If a tool always gives the wrong result, it lacks accuracy.
If a measurement is inconsistent, it cannot be accurate because it doesn’t reflect the true value.
Criterion Validity
The extent to which a measurement
instrument accurately predicts behavior in a particular area
types of Criterion Validity:
Predictive and Concurrent
Predictive Validity
Give a test at some point in time,
compare the score to future criterion behavior
Concurrent Validity
Give a test and then immediately
evaluate criterion behavior
Reactivity
subject’s behavior changes
because of the awareness of the observer
Allow the subject to get used to the observer and environment
Conceal observer
Allow for anonymous responding
Nonreactive or unobtrusive measures
indirect observations of behavior
Ex: Observe graffiti or
Count beer bottles in the trash.
may or may not
involve intervention by the researcher
chi-square test of independence:
a test of significance for nominal data
f there is no difference between the proportions for the groups
