-4
-3
-2
-1
0
1
2
3
4
0
6
12
18
0
6
12
18
0
6
12
18
0
6
12
18
0
6
12
18
0
6
12
18
0
6
12
18
time (EDT)
z score
9/8/01
9/14/01
9/11/01
6:30 AM
noise
Sept 8 – Sept 14
“signal”
“signal”
