Lecture 2 – Terms & Concepts
Friday, September 13, 2013
1. Independent and dependent variables
1. DV – Dependent Variable - an “outcome”
2. IV – Independent Variable - a “predictor”
Sometimes there is no correlation. When there is no IV/DV, you are looking for a
relationship between the two.
IV affects the DV
age affects income
income affects the size of house
Levels of measurement
i. Binary ( e.g., yes/no)
Can only be one of two options.
ii. Nominal (e.g., race: black, white, Latino, Aboriginal, Asian, other)
No order. Essentially they are names.
i,e, 0 = Asian, 1 = Black, 2 = White, etc. These numbers do
not mean one is better or has an ordering. These are just a
representation for a name for analysis purposes.
iii. Ordinal (e.g., 1=strongly disagree to 5=strongly agree; low, medium,
Some sort of order. Low – high or vice versa. No set distinction
between the two. Similar to a survey where there is a ranking
b. Continuous *On the midterm*
i. Interval – p.10 (also on Field p. 10) – “equal intervals on the
variable represent equal differences in the property being measured
(e.g. the difference between 6 and 8 is equivalent to the difference
between 13 and 15).”
The distinction between the two is not always clear. However, it
does not always matter. As long as it is continuous, it is okay.
There is no real 0 point.
Temperature system. In Fahrenheit, 0 does not mean an
absence of temperature.
Time. No absence of time of day. No certain time of day is
twice of another.
ii. Ratio – you can create a meaningful ratio. E.g., 6 is twice as much as
3. There is a meaningful 0 point. Means an absence of
0 income means an absence.
Running speed. When you're standing still, there is a speed
c. Measurement error