Figure 3:
Probability distribution of
Δ
𝑋
. We adopt the method of nonlinear least square to estimate the exponent.
S
l
o
p
e
=
1
.
0
7
,
S
S
E
=
1
×
1
0
−
4
,
𝑅

s
q
u
a
r
e
=
0
.
8
9
9
9
, and
R
M
S
E
=
7
.
9
×
1
0
−
4
.