Chapter 2: Basic Concepts Flashcards
(15 cards)
Nominal Scale
- Numbers used to distinguish objects
- Used for classification & incorporating categorical data
- Categories are mutually exclusive; members of one category are qualitatively different than members of any other category
- -Only wat to measure a qualitative variable
Ordinal Scale
- Numbers used to place objects in order
- Differences b/w each set of points on the scale aren’t obvious
- -Only ranks items
- Possess property of magnitude, not equal intervals
Interval Scale
- Numbers indicate order of items with equal intervals b/w objects representing equal differences
- Equal intervals b/w objects representing equal differences
- -Differences are meaningful
- Lacks an absolute or rational zero (a value which represents the complete absence of the characteristic being measured)
Ratio Scales
- Identical to the interval scale except that it has a true zero point
- -Ie. Kelvin
- Has all properties of magnitude, equal intervals & rational zero
Discrete Variable
- Take on a small set of possible values
- -Ie. Gender, marital status etc
Continuous Variable
- Takes on any value
- -Ie. Speed
Independent Variable
- Controlled by the experimenter
- -A variable we manipulate
Dependent Variable
- Variable we measure
- Data or score
Random Assignment
- Allocation/ assignment of participants to groups by a random process
- -Even more important than random sampling
- -Ensures the differences b/w groups strictly reflects the differences b/w experimental treatments & nothing more
Scales of Measurement
- Characteristics of relations amongst numbers assigned to objects
- Not all variables
- -Are measured in the same manner
- -Carry the same meaning
- -Are interpreted in the same way
How we measure data will influence how we interpret it
The Role of Measurement Scales
-Ensures measurements are as close as possible what’s being measured, results obtained are true and the relationship b/w those numbers and underlying objects/ events/ interpretations = strong
Parametric
Interval/ Ratio measurements
Nonparametric
- Nominal/ ordinal data
- Categorical measurements (frequencies)
Variable
- Properties which can take on different values
- -Any measure or characteristic that we use in statistics
Random Sampling
Every score in the population has an equal chance of being included in the sample
