Thursday, 12 March 2015

Cleaning data set

Cleaning data set in SPSS
https://www.youtube.com/watch?v=Ik4Dyn8e8vA

Skewness and kurtosis
https://www.youtube.com/watch?v=w8-wf6lBh8M

Multivariate outlier (mahanalobis distance) SEM - AMOS
https://www.youtube.com/watch?v=0vtgynhkH60&feature=youtu.be

Model fit during a Confirmatory Factor Analysis (CFA) in AMO
This is a model fit exercise during a CFA in AMOS demonstrates how to build a good looking model, and then address model fit issues, including modification indices and standardized residual covariances.  also discuss briefly the thresholds for goodness of fit measures
https://www.youtube.com/watch?v=JkZGWUUjdLg

Outlier (mahanalobis distance)
SPSS
https://www.youtube.com/watch?v=WSflSmcNRFI

Plugin EFA and CFA data in amos 18
https://www.youtube.com/watch?v=sLtMOFcojZY

 http://stackoverflow.com/questions/19130917/how-to-fix-amos-error-observed-variable-is-represented-by-an-ellipse-in-the-pa

IBM Help discusses this error but isn't that helpful.
In practice, I've seen this error come up a number of times. It can occur because you have incorrectly specified a variable as latent that you wanted to be observed. However, more commonly, it is the result of giving an inappropriate variable to a latent variable. Specifically, it is relatively easy to give a name to a latent factor that is the same as an observed variable in your data file.
For example, one time I had some personality variables in a dataset and the extraversion items were called E1, E2, E3, and so on. These are common names for residuals. So when giving residuals these names, there was a conflict with the names in the data file. Another even more common cause is when you name a latent factor an appropriate name (e.g., selfesteem, extraversion, jobsatisfaction, etc.) and you have already created a scale score in your data file with the same name. This also causes the conflict.
The basic solution is just to give the variable a latent variable a unique name that doesn't conflict with one in the data file. So for example, name the variable selfesteem_factor rather than selfesteem if you already have a variable called selfesteem

Reverse coding in spss
https://www.youtube.com/watch?v=IDK_u4l7vJI  (part 1)
https://www.youtube.com/watch?v=IkTvKf5nFsY (part 2)

Super easy to understand - reverse coding
https://www.youtube.com/watch?v=uzQ_522F2SM