Geography Reference
In-Depth Information
p
1
p
WQ
(
w
v
)
/
w
i
i
i
(17)
i
i
1
where, WQ = value of concerned water quality variable, w
i
= weight value for
the i
th
point, v
i
= point value of the i
th
point, and p = total number of points
within the limiting distance.
Table 3. Summary of the goodness-of-fit criteria
Goodness-of-fit
Criteria
S. No.
Equation
1
n
ME
z
(
x
)
z
*
x
)
Mean Error
(ME)
i
i
n
1
i
1
Where, z(x
i
) and z*(x
i
) = observed and estimated values of
variable z at t
he location x
i
, and n = num
ber of data points.
n
Root Mean
Squared Error
(RMSE)
2
z
(
x
)
z
*
x
)
i
i
2
i
1
RM SE
n
Correlation
Coefficient (r)
(Rodgers and
Nicewander,
1988)
n
n
n
n
z
(
x
)
z
x
)
z
(
x
)
z
x
)
i
i
i
i
i
1
i
1
i
1
r
3
n
n
2
2
2
2
n
z
(
x
)
z
(
x
)
n
z
x
)
z
x
)
i
i
i
i
i
1
i
1
1
M SE
(
x
)
Mean Standard
Error (MSE)
k
i
4
n
Where,
(
x
)
= estimation variance at the location x
i
.
k
i
Mean Reduced
Error (MRE)
(Vauclin et al.,
1983)
1
n
M RE
z
(
x
)
z
x
)
/
(
x
)
5
i
i
k
i
n
i
1
Reduced
2
R
e
S
Variance (
2
1
n
2
R
S
z
(
x
)
z
(
x
)
/
(
x
)
6
i
i
k
i
)
(Vauclin et al.,
1983)
n
e
i
1
