[L2] Descriptive Statistics Flashcards
Used with ordinal data or with non-normal distributions.
INTER-QUARTILE-RANGE
A ___ is drawn for each category, where the height of the
bars represent the frequency or number of members of
that category.
bar
indicates the
percentage of scores that fall below the upper limit of
each interval
Cumulative Percentage Distribution
How to compute the Median
- Scores should be placed in ascending order of size, from
the smallest to the largest score. - When there is an odd number of scores in the
distribution, halve the number and take the next whole
number up. - If there are an even number of scores, the median is the mean of the two middle scores.
Instead of using bars, a ____ is plotted over the midpoint
of each interval at a height corresponding to the
frequency of the interval. Points are joined by a ___-
point; straight
line.
To find the range we find the ____ value (2) and the
____ value (17).
lowest; highest
The computer defines that point as an ____.
outlier
- Called the ___ mean.
- Calculated by adding up all the scores and dividing by the
number of individual scores.
arithmetic; MEAN
if outliers can not be eliminated and you are convinced
that you have a genuine measurement, then you have a
___.
dilemma
When the distribution is ____ (i.e. has one mode) and
____, then the mode, median, and mean will have
very similar values.
unimodal, symmetrical
It is the distance between the highest score and the lowest
score.
range
_____ sometimes occur most commonly when we
are trying to ask questions to measure the range of some
variable, and the questions are all too easy, or too low
down the scale
Ceiling Effect
(e.g., histograms, bar chart etc) – is used to present
the pattern in the data.
Charts
small sample size, not normally distributed
nonparametric test
Loosely known as the average. In statistical description,
though, we have to be more precise about just ___ we mean.
what sort
of average
____should not overwhelm the reader who is
trying to see what is going on.
Data presentation
But as long as the assumptions are __ to any
great extent, we will be OK.
not violated
The downfall of the mean is that it is affected by ___
skew and
outliers.
The median is ____than the mean to extreme
scores.
less sensitive
___ occurs when only few of the subjects are
strong enough to get off the floor.
Floor Effect –
when data are measured on an ____, it is tricky
and difficult to decide whether to use the mean, median,
or even the mode
ordinal scale
The ___ then extend from the box to the highest
and lowest points – unless this would mean that the
length of the whisker would be more than 1.5 times the
length of the box.
whiskers
There are ____that can be used to
draw a normal distribution. These equations can be used
in statistical tests.
mathematical equations
Small number of data points that lie outside the
distribution when the distribution is approximately
normal.
OUTLIERS