A

B

C

D

And

Sample size

100

99

100

86

100

Get to the bottom of the grades

41.23 ± 8.17

41.14 ± 7.47

42.76 ± 7.67

36.26 ± 6.27

43.18 ± 8.28

Measured results

41.31 ± 10.04

42.41 ± 8.62

41.46 ± 8.04

39.08 ± 9.13

45.74 ± 8.16

T

0.112

2.252

−1.912

3.788

−4.202

P

0.911

0.027

0.059

<0.05

<0.05