Assessment

Period

Cohort

M

SD

National Norm M

t

P

January 2020

463.46

48.89

552.5

−23.67

<0.001

August 2020

477.17

52.77

557.5

−19.79

<0.001

January 2021

492.56

48.70

590.5

−26.14

<0.001

May 2021

507.39

47.81

616.0

−29.53

<0.001

August 2021

506.06

44.75

616.0

−31.94

<0.001