exploratory factor analysis Flashcards
what is exploratory factor analysis?
to uncover the underlying structures of a relatively large set of variables.
describe variability among observed correlated variables in terms of a potentially lower number of unobserved variables known as factors.
what types of factor analysis are there?
1) exploratory factor analysis
2) confirmatory factor analysis
what is the purpose of EFA
to identify underlying rs between measured variables
what are the 3 goals of EFA?
1) to identify factors based on data
2) maximise the number of variance explained
3) minimise the number of factors
is it required to have a hypothesis for EFA?
no
what tests do u use to determine correlation?
1) correlation matrix
2) factor matrix/ factor structure
what does a -1 or 1 for correlation matrix imply about correlation?
correlation with HIGH magnitude
what does a 0/ near 0 for correlation matrix imply about correlation?
correlation with LOW magnitude
what is the weakness of EFA
difficult to make judgement as there are too many factors.
what is the assumption of the data for EFA?
1) sample should be large enough
2)variables should be interval/ ratio scale
what are the 2 assumption checks you have to do for EFA?
1) KMO- kaiser- Meyer - Olkin
2) Bartlett’s test of SPHERICITY
what does KMO, kaiser meyer olkin measure?
sampling adequacy
what is the good value for KMO?
0.8 and above
what does bartlett’s test of sphericity check?
whether correlation between items are significant
what does p value <0.05 for bartlet’s test of sphericity indicate?
p value < 0.05 indicates your data is suitable for factor analysis
