Hoofdstuk 1
Types of data and measurements
Qualitative and Quantitative Variables
- kwantitatief numeriek
- kwalitatief categoriaal
numeriek discreet, continu = kwantitatief
categoriaal dichotoom, nominaal, ordinaal = kwalitatief
The Hierarchy of Measurement Scales
different scales:
- nominaal (zwakst)
- ordinaal
- interval
- ratio (sterkst)
Dichotoom:
Nominal Scale meerdere opties
Ordinal Scale meerdere categorien
Numeriek:
Interval Scale meerdere categorien + distance is known and equal, bijv: temp in C
Ratio Scale meerdere categorien + distance is known and equal + absolute nul
(Complete absence), bijv: leeftijd
detect differences, direction of the difference, size of the difference, calculate ratios
,Frequency distributions
Frequency Distributions
ordering scores
Frequency Distribution Tables
frequency measures: absolute, relative (nog niet x 100!), percent (wel x 100!)
cumulative frequency measures: cumulative, cumulative relative (niet x 100!), cumulative percent
Voorbeeld:
Frequency Distribution Graphs
use of charts:
- bar chart kwalitatief
- histogram kwantitatief
- ogive cum. frequencies
,voorbeeld ogive:
Shape of a Distribution:
Symmetrical, uniform, positively skewed,
negatively skewed
scheef rechts / positief scheef (skewed = scheef) scheef links / negatief scheef
Measures of Location I: Quantiles
Percentile rank
The percentile rank of a score is the percentage of scores in the distribution that are equal to or
lower than it.
number of scores (equal or lower) : total score x 100
(n: 12 / n:16) x 100 = 75% = 75
, percentiles
i = integer → positie van de variabelen!! - in volgorde
Quantiles
If you divide the data set into k equal parts, you call the dividing values k-quantiles and there are
always k−1 quantiles.
Quartiles: gewoon deze formule aanhouden
i = integer → positie van de variabelen!! - in volgorde
linear interpolation: used when integer is not discreet
measures of central tendency
Introduction to Central Tendency
Central tendency is a statistical measure that is used to identify a single score that describes the
center of a distribution.
- mode, median, mean
Mode most frequently occurring }
- 2 mode’s bij bimodal or more = multimodal
- no mode
Types of data and measurements
Qualitative and Quantitative Variables
- kwantitatief numeriek
- kwalitatief categoriaal
numeriek discreet, continu = kwantitatief
categoriaal dichotoom, nominaal, ordinaal = kwalitatief
The Hierarchy of Measurement Scales
different scales:
- nominaal (zwakst)
- ordinaal
- interval
- ratio (sterkst)
Dichotoom:
Nominal Scale meerdere opties
Ordinal Scale meerdere categorien
Numeriek:
Interval Scale meerdere categorien + distance is known and equal, bijv: temp in C
Ratio Scale meerdere categorien + distance is known and equal + absolute nul
(Complete absence), bijv: leeftijd
detect differences, direction of the difference, size of the difference, calculate ratios
,Frequency distributions
Frequency Distributions
ordering scores
Frequency Distribution Tables
frequency measures: absolute, relative (nog niet x 100!), percent (wel x 100!)
cumulative frequency measures: cumulative, cumulative relative (niet x 100!), cumulative percent
Voorbeeld:
Frequency Distribution Graphs
use of charts:
- bar chart kwalitatief
- histogram kwantitatief
- ogive cum. frequencies
,voorbeeld ogive:
Shape of a Distribution:
Symmetrical, uniform, positively skewed,
negatively skewed
scheef rechts / positief scheef (skewed = scheef) scheef links / negatief scheef
Measures of Location I: Quantiles
Percentile rank
The percentile rank of a score is the percentage of scores in the distribution that are equal to or
lower than it.
number of scores (equal or lower) : total score x 100
(n: 12 / n:16) x 100 = 75% = 75
, percentiles
i = integer → positie van de variabelen!! - in volgorde
Quantiles
If you divide the data set into k equal parts, you call the dividing values k-quantiles and there are
always k−1 quantiles.
Quartiles: gewoon deze formule aanhouden
i = integer → positie van de variabelen!! - in volgorde
linear interpolation: used when integer is not discreet
measures of central tendency
Introduction to Central Tendency
Central tendency is a statistical measure that is used to identify a single score that describes the
center of a distribution.
- mode, median, mean
Mode most frequently occurring }
- 2 mode’s bij bimodal or more = multimodal
- no mode
