Table 3:
Mean and standard deviation of the cell density (number of cells per 10,000
μ
m
2
area) in all four zones.
Zone 1
Zone 2
Zone 3
Zone 4
16–20 yrs
3
.
6
6
±
2
.
3
5
2
.
5
6
±
1
.
8
8
2
.
8
2
±
1
.
1
1
3
.
6
2
±
1
.
6
5
21–30 yrs
6
.
9
7
±
4
.
3
4
3
.
2
0
±
1
.
6
5
2
.
8
3
±
1
.
3
5
2
.
7
4
±
1
.
2
3
31–40 yrs
3
.
7
9
±
1
.
5
9
3
.
1
9
±
2
.
2
4
2
.
2
9
±
0
.
2
6
1
.
9
4
±
0
.
1
5
41–50 yrs
5
.
9
9
±
3
.
2
9
2
.
3
4
±
0
.
7
0
3
.
1
4
±
0
.
4
5
3
.
5
7
±
1
.
4
5
51–60 yrs
9
.
0
3
±
3
.
4
1
4
.
3
6
±
2
.
2
2
4
.
2
8
±
0
.
9
4
4
.
0
3
±
0
.
5
6
61–70 yrs
9
.
2
9
±
0
.
7
1
3
.
1
1
±
0
.
5
0
3
.
7
6
±
1
.
2
7
4
.
9
5
±
1
.
2
3
71–80 yrs
3
.
0
5
±
0
.
4
7
1
.
6
3
±
0
.
4
5
2
.
0
0
±
0
.
3
3
1
.
8
6
±
0
.
3
5
81–90 yrs
4
.
5
6
±
1
.
6
3
3
.
3
1
±
1
.
3
4
3
.
1
3
±
1
.
2
9
2
.
8
8
±
1
.
3
2