Table 3. Descriptive statistics for each variable for the four float samples. SD is the standard deviation. Q1 is the first quartile (25% of teeth lie at or below Q1) and Q3 is the third quartile (75% of teeth lie at or below Q3).
(n=51)
(n=101)
(n=102)
(n=193)
Geological age (Ma)
Length (mm)
Mean (SD)
Min, Max
median [Q1, Q3]
12.8 (2.8)
7.7, 19.0
12.4 [10.7, 15.1]
17.1 (3.7)
9.6, 26.9
17.2 [14.3, 19.0]
16.7 (3.3)
8.9, 24.4
17.2 [14.2, 18.6]
22.4 (4.7)
8.8, 35.5
22.1 [19.1, 25.4]
Ratio
Mean (SD)
Min, Max
median [Q1, Q3]
0.27 (0.03)
0.23, 0.33
0.26 [0.25, 0.29]
0.21 (0.04)
0.12, 0.35
0.21 [0.19, 0.23]
0.22 (0.03)
0.11, 0.30
0.18 (0.04)
0.18 [0.15, 0.20]
Number of serrations
Mean (SD)
Min, Max
median [Q1, Q3]
9.1 (1.2)
7.0, 11.0
9.0 [8.0, 10.0]
12.7 (1.9)
8.0, 18.0
13.0 [11.0, 14.0]
13.1 (1.9)
8.0, 18.0
13.0 [12.0, 14.0]
15.8 (3.0)
8.0, 28.0
16.0 [14.0, 17.0]
Avg. serr. width (mm)
Mean (SD)
Min, Max
median [Q1, Q3]
1.02 (0.18)
0.67, 1.34
1.01 [0.89, 1.16]
1.05 (0.16)
0.70, 1.57
1.04 [0.95, 1.15]
1.00 (0.15)
0.66, 1.45
1.00 [0.89, 1.10]
1.17 (0.14)
0.74, 1.60
1.17 [1.06, 1.27]