variable - can take diff values for diff individuals
s
Dataset contains info about all variables
-s
conclusions j
based om
sample
population
of
D
measurmant
8s
Levels
:
nominal
L
categorizing
sample
categorical
ranking
ordinal
-logical
continonos interval tnumerical
ratio scaleabsolute zero
,:
population group researchers want info about
-entire
sample smaller group drawn from population
-
L Representative characteristics of population mirrored -3
,
2
II population
letters sample
population -3
greek
mean
sample letters deviation standard s o
-sroman
Descriptive statistics
When the sample size is
exactly the
population size
inferential statistics
is smaller than the
population size
When the sample size
often observed
Frequency how values are
-
* Absolute
frequency the number I count
:
* relative
frequency the number of times percentage as a
:
num ber of
compared to valid
* frequency
the answers
valid
-
cumulative frequency
the relative frequencest the centages
per
:
of the previous
groups
, The mode = the most observed value ( can be two
there
)
Ls for nominal I ordinal
L ,
for ratio I interval use the mean
,
convention the
-
people agreeing
on
using same
symbol
Şî Xi sum all values
=s
average grades
-
M - of
s
number
=
w
X -7 : t third value e
theh (3- indextJinderzi
-sxi
=value
x3
E add all that comes after it - E Xi add all values
starting
at the first
-
=
s
?
N of values is 1, so start at 3, neculs walues so add all values
=number
,
M
-mean
The median is a measure of centre clike the
means outliers have less effect
,
Ls order values count values split in two & round up count
,
,
,
to that middle walue
even even values : middle value mean of middle two values
,
Bar
graph Histogram
:
Eo
:
Idedts Ieallank
gron
ronge
.
-
max
-min
,
groups
- I ordinal - & interval
ratio
nominal
- are separated - are connected
bars
bars
Quartiles the values that split your data into four equal parts
Ls even values
:
take the mean of the values the
254
42 as
5 25%. 25%.
quartile falls between
y.
sIQR Linterquartile Ranget distance between Q middle 50%
3IQIthe
variation = differences between data and from the measure of centre
L
Boxplot visualises variation
:.
.
* middle bar median
:
* BoX middle 50%
:
* Limes : rest of the data
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller soraya35. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $5.48. You're not tied to anything after your purchase.