Center class (cm)

With stratification

Without stratification

N observed

14.5

2657.2

2696.9

2619

24.5

1248.5

1031.1

1263

34.5

592.9

486.5

643

44.5

349.8

269.0

351

54.5

234.9

184.2

245

64.5

129.5

95.2

140

74.5

61.2

47.8

64

84.5

28.0

17.9

26

94.5

13.0

7.6

13

≥104.5

8.0

7.1

7

∑

5323.1

4843.2

5371