Hi there! I was wondering if anyone could help me figure out why I am getting the wrong results!
I am using the PISA dataset of 2012 to calculate the variance explained by ESCS.
I followed the steps in the PISA DATA ANALYSES Manuel 2nd edition for SAS:
1. SASĀ® syntax for preparing a data file for the multilevel analysis (Box 16.3 at p.238-239).
2. SASĀ® syntax for running multilevel models with the PROC_MIXED_PV macro (Box 16.6 at p.242).
3. Calculating the results:
-> I used following equation:
1-(T2/T1)
T2 = is the intercept/between-school variance in model 2 and;
T1 = is the intercept/between-school variance in the empty model
First I tried using SPSS, than SAS, but either way I am not getting the same results as in the examples given by PISA.
For example: According to PISA, in Norway, 7% of variance in math performance is explained by ESCS. According to my calculations that is wrong, as much as 20% is explained by ESCS, and 25% by ESCS and MU_ESCS.
Interestingly when I run a one-way ANOVA, than the R-square displays (almost) the same number as in the examples by PISA.
I only have a few more days left before submitting my BA Paper, and I really need to calculate the variance for countries that are not included in the examples on PISA's website.
Can someone please please help me figure out why I am not getting the right number.
I am using the PISA dataset of 2012 to calculate the variance explained by ESCS.
I followed the steps in the PISA DATA ANALYSES Manuel 2nd edition for SAS:
1. SASĀ® syntax for preparing a data file for the multilevel analysis (Box 16.3 at p.238-239).
2. SASĀ® syntax for running multilevel models with the PROC_MIXED_PV macro (Box 16.6 at p.242).
3. Calculating the results:
-> I used following equation:
1-(T2/T1)
T2 = is the intercept/between-school variance in model 2 and;
T1 = is the intercept/between-school variance in the empty model
First I tried using SPSS, than SAS, but either way I am not getting the same results as in the examples given by PISA.
For example: According to PISA, in Norway, 7% of variance in math performance is explained by ESCS. According to my calculations that is wrong, as much as 20% is explained by ESCS, and 25% by ESCS and MU_ESCS.
Interestingly when I run a one-way ANOVA, than the R-square displays (almost) the same number as in the examples by PISA.
I only have a few more days left before submitting my BA Paper, and I really need to calculate the variance for countries that are not included in the examples on PISA's website.
Can someone please please help me figure out why I am not getting the right number.
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