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College notes Introduction To Research Methodology - Pre-Master 's Social Research Methods, ISBN: 9780199689453 $9.18   Add to cart

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College notes Introduction To Research Methodology - Pre-Master 's Social Research Methods, ISBN: 9780199689453

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Notes from research methods, stats+methodology

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  • January 18, 2021
  • 18
  • 2019/2020
  • Class notes
  • Matthijs
  • All classes
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Exam Review (Statistics)

Big Picture
1. Descriptive and univariate statistics show minor info regarding samples (dispersion,
mean…)
2. Bivariate Statistics focus on viewing if relations between variables is present
3. T-test & ANOVA focus on seeing if effects of a given variable are the same among different
groups
Notes
 Univariate Statistics (focus on one variable and its properties)
 Measurement Levels
o Nominal
 Basic distinction between categories
Categorical  Eg: religions, sex, colors…
o Ordinal
 Distinction between categories and ranking of value
 Eg: Low-medium-high, top 5 favorite food…
o Interval
 Distinction between categories, ranking of value and equal sized
intervals
 Eg: Temperature in Celsius, age in years, population, hours spent,
Continuous income…
o Ratio
 Distinction between categories, ranking value, equal sized intervals
and natural zero point
 Eg: time, temperature in Kelvin
 Describing Frequencies
o Describing Frequencies may be very simple in certain cases, in others
however, it is necessary to rely on proportions to create a reasonable
comparison
Frequency
 Proportion=( )∗100
Number of samples
F
 P=( )∗100
N

2016-2017 2017-2018
W Europe 6 12
N America 10 9
Total 16 21
 Eg: Origin of Pre-Maters students
6
 PWE = ( )
16
∗100=37.5 %

 Describing Distribution
o Mode
 Category with most observed subjects
 Eg: W. Europe 2017-18

, o Median
 Middle value after numbers are ranked in increasing order
 Requires ordinal measurement level at minimum
 Odd numbers just pick middle number
 Eg: 6,9,10,12,14
 Median= 10
 Even numbers, simply add the two middle numbers and divide by 2
 Eg: 6,9,10,12
 (9+10)/2=(19)/2=9.5
o Mean
 Arithmetic average of all samples
 Requires interval or ratio level variables
 Formula
of all sample results
 Mean= ∑
Number of samples
Σx
 M=
N
o Range
 Indicates the difference between the lowest score and highest score
 Formula
 Range=x −X
o Interquartile Range
 Similar to range but focuses on values within the 75% and 25%
quartiles
 Formula
 IR=Highest qvalue (75 %)−Lowest qvalue( 25 %)
Measure of Dispersion When to use it
Mode  Nominal measurement levels
Median  Ordinal measurement levels
Mean  Interval/Ratio measurement levels

 Deviations from mean
o Deviance
 How far is a given variable from the mean
 Formula
 Deviance=variable−mean
 D=x i−x
o Variance
 How close around the mean is the data (same as standard deviation)
 Formula

for each variable :( variable−mean)then add all of them up
Variance=
Number of Samples−1
2 Σ( x i−x )
 σ =
N−1
o Standard deviation
 Similar to variance but expressed in a scale compatible with variables

, Grants some indication of how data is dispersed
Formula

each variable :(variable−mean)then add all of them up
Stand . Dev .=√
Number of Samples−1
Σ(x i−x )
 σ =√
N −1
o Degrees of Freedom
 Indicate how many variables are present, each time one is used a
degree of freedom is lost



 Scores & Standardization
 Types of distribution
o Skew
 Positive
 Negative




o Kurtosis
 Leptokurtic (+2.6)
 Platykurtic (-0.9)




o Bimodal distribution

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