Lecture Goals
    You should be able to distinguish bewteen:
        - Continuous and Discrete variables
        - Nominal, Ordinal, interval, and Ratio scales

    You should be able to identify the meaning of basic statistical symbols
 
 

Reading
    Chapter 2
 
 

Measurement
    Informal Definition
        = Describing something in terms of ______________________

           Examples of standardized units:
 
 

Variables & Measurement
    Continuous Variables
        = variables expressed as numbers

        = numbers are part of a ____________________________

        Examples:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

    ** Possible to score a infinite number of #s **
 

Discrete (Categorical) Variables
    = variables expressed as ________________

    = no intermediate values

    = variables can be expressed as #' s (#'s serve as data _____________)

    Discrete Variable Examples:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

    ** Numbers are NOT on a number line **
 
 
 

Types of Scales
    Nominal Scale
    Ordinal Scale
    Interval Scale
    Ratio Scale
 

Nominal Scales
    Units = non-quantitative _______________
    Examples:
 
 
 
 
 

    No meaningful relationship between #'s assigned to represent categories

    ** ________________ # labels to do meaningful math **
 
 

Ordinal Scales
    Units = _____________________(thinner, faster, first)

    Involves comparisons of _______________________________

    Examples:
 
 
 
 

    Only ______________________________________ comparisons

    Does not Include information about _______________________

    Example:
 
 

Interval Scales
    Units = quantitative categories that are ___________________________________

    Value of differences can be ______________________ rather than just relative (ranking)
 
 

Ratio Scales
    Same as Interval Scales but ________________

    Units = ____________________________________

    Promotes __________________ across tests

    Can compare __________________________

Basic Symbols
    N = _________________
 
 

E = _______________
    Means "Add" or "Sum"
___________________
 

E Xi is also written as E X
** Watch the parentheses **

E X + 3 vs. E (X + 3)
    E X + 3 = sum x values and then add 3
    E (X + 3) = add 3 to each x value and then sum
 

E X + 3 =(120+140+100+120)+3 = 483
E (X + 3) = (120+3)+(140+3)+(100+3)+(120+3) = 492
 

(E X)² = (sum of X)²
    Calculating (E X)²:

        1) get __________

        2) _____________
 
 

                                (E X)² = (120+140+100+120)² = (480) ² = 230400
 
 

(E X)² is different from E X²
E X² = sum of the X² values
 

Calculating E X²:

    1) get all of the individual __________

    2) _______________________
 
 

E X² =14400+19600+10000+14400 = 58400
 
 

Homework
    Chapter 2: 1 - 13