Variables and Their Measurements Flashcards
What are variables?
characteristics of persons or things
Give examples of variables.
- hair colour
- reaction time
- sex
- skill as measured by some performance test
What are the 2 types of variables?
- discrete
- continuous
What are discrete variables?
measures that can take on only separated values
What are separated values?
there cannot be any fraction or “in between” value
Give examples of discrete variables.
- sex
- skill in performance when measured by acquisition of points on trials
- number of participants on a team
What are continuous variables?
- a measure that can take on any value within a certain range
- quantities such as height, weight, or reaction time, where the increments form a continuum
Give an example of a continuous variable.
if a person says he weighs between 150 and 151 pounds, he can actually weigh any fraction of the one pound differential
What forms a continuum?
increments of continuous variables
Continuous variables are only limited by ….
the accuracy desired and limits of the instrumentation
Why is it unlikely to know the exact value of a continuous variable?
- regardless how accurate measurements are, they always fall short of their exact value
- we always end up rounding off at some decimal point
What is the reported value?
Even though we never know the exact value of a continuous variable, we have to report some kind of a figure
What is sensitivity?
The limit imposed on a reported value of a continuous variable
The sensitivity of a measuring process is represented by …
the smallest unit of the reported scale of the measuring instrument
The sensitivity of 1.326 inches is…
- to the nearest thousandth of an inch
or - to 0.001 inches
