Psychological Statistics Flashcards
Nominal Scale of Measurement
Name different categories
No quantitative properties
Numbers are just used as names
Ordinal Scale of Measurement
Numbers differentiate categories or instances
Numbers convey an ordered series of relationship
Can’t assume equal increments (1 to 2)
Example? Ranks
Interval Scale of Measurement
Has all properties of nominal and ordinal
A numerical difference means the same thing across the scale
Zero does not mean absence of thing measured
Example? degrees F, C, or
Ratio Scale of Measurement
Has all properties of nominal, ordinal, and interval
Zero point is absolute
Example? time, degrees K
discontinuous (discrete) variable
Variable for which only a finite number of values can occur between any two points
E.g. 1 person or 3 persons not 1.5 person or 2.7 person
Continuous variables
Theoretically can assume an infinite number of values between any two points
E.g. height, age, reaction times
independent variable
the variable manipulated by the researcher
dependent variable
the variable being measured by the researcher
Real (true) limits
applied to a continuous variable and it is (+/-) one half of the unit measured (decimal place). E.g.
47 + .5= 47.5
47 - .5= 46.5
or 47.5 + .05= 47.55
47.5 - .05= 47.45
Rounding Conventions
Round to two decimal places
Greater than 5 round up
Less than 5 leave unchanged
Exactly 5 round up to nearest even digit if not already there
6.575 –> 6.58
6.525 –> 6.52
Frequency Histogram
frequency polygon
Line Plot
Mesokurtosis
Platykurtosis
