Table 2 Summary statistics for non-parametric comparison of composite z-scores for four cohorts of DEP and GEP students

Cohort 1 SC1 (2008-2009)

-1.07

2.44

4.64

3.71

2390

<0.01

0.35

Cohort 1 SC2 (2009-2010)

-0.33

0.58

1.42

0.76

2464

<0.01

0.33

Cohort 2 SC1 (2009-2010)

-0.82

2.42

4.87

3.25

2449

<0.01

0.40

Cohort 2 SC2 (2010-2011)

-0.05

0.50

1.38

1.31

3248

<0.01

0.28

Cohort 3 SC1 (2010-2011)

-1.29

2.88

5.04

3.05

2000

<0.01

0.45

Cohort 3 SC2 (2011-2012)

-0.21

0.61

1.44

0.75

2426

<0.01

0.37

Cohort 4 SC1 (2011-2012)

-0.99

2.78

5.29

3.80

2728

<0.01

0.40

Cohort 4 SC2 (2012-2013)

-0.21

0.58

1.39

1.04

2924

<0.01

0.35