Quick Review Flashcards
(39 cards)
What are the four common scales of measurement?
Nominal, Ordinal, Interval and Ratio
What is the main differences between an interval and a ratio scale?
Interval: values but they are equal
Ratio: there is an aboslute zero- one is always better then the other
The most important characteristic behind using different scales is to keep in mind the numbers themselves (T OR F)
false; what is important is the underlying variable that we hope that we are measuring
What is the practical distinction between discrete and continous variables?
Discrete variables take on only a few different values, but continous variables can take on any value between the lowest and highest score
What is the independent variable?
I: the variable is the one that is manipulated to get a result
what we are trying to study, as opposed to the score we obtain
To oversimplify, random selection is useful to ________ while random assignment is useful to ______
- assure that we can generalize to the population from which we sampled
- assure that differences between groups are not due to extranoues variables
When we refer to X , we are refering to
any specific variable
What is the general rule about parentheses in an equation?
DO IT FIRST
BEDMAS MOFO
THE NOTATION Σ MEANS:
THE SUM
What is the purpose of plotting data?
to make it interpretable
the endpoint of an interval are called
the real upper and lower limits
a figure that plots various values of the dependent variable on the X axis and the frequencies on the Y axis is called:
frequency distribution (histogram)
The optimal number of intervals for a histogram or a stem leaf is:
whatever makes the most sense and is the most useful for that specific data set
^^ how fucking helpful
List three important things about stem leaf plot
used to present the shape and the values of score, back to back to show two related scores and adjusted to handle different sized values
List the three terms that describe the shape of a distribution
symmetry modality and skewness
a positively skewed distrubition has a tail stretching out to the right T OR F
T
A MAJOR CHARACTERISTIC OF A GOOD GRAPHIC IS
SIMPLICITY
Which of the measures of central tendency are you most likely to see everywhere?
the mean
What do we report when a distribution has two distinct and non adjacent modes
REPORT BOTH PEAKS (BI-MODAL) - both significantly large but maybe not the same
When is the median most useful?
when we dont want the extreme score to influence the result
Give two advantages to the mean
more stable estimate of the central tendency of the population in over-repeated sampling and it can be algebraically
Why do we use trimmed samples
To eliminate the influence of extreme scores
What is a good percentage to trim?
10-20%
Define an outlier
an extreme and unusual score on a box plot
