srarre
NOTES
-
I
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
NOTES
-
I
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
