HP 12c Platinum - Page 91

Forecasting 91
12c platinum / 12C
RPN Keystrokes
12c platinum
ALG Keystrokes
Display Comments
:2 :2
25.11
Smoothing average (S
t-1
).
:3 :3
0.42
Trend (T
t-1
).
:6 :6
25.95
Last forecast D
ˆ
(
t+1
).
The procedure is repeated for several
α 's.
Smoothing Constant (α) .5 .1 .25 .2
Cumulative Error (Σe
2
) 23.61 25.14 17.01 18.03
For the selected α = .25 S
t+1
= 24.28
T
t-1
= 0.34
D
ˆ
t+1
=
25.64
Forecasting:
12c platinum / 12C
RPN Keystrokes
12c platinum
ALG Keystrokes
Display Comments
fCLEARH fCLEARH
0.00
1\ 1-
1.00
.25?0- .25?0³
0.75
?1 ?1
0.75
24.28?2 24.28?2
24.28
.34?3 .34?3
0.34
25.64?6 25.64?6
25.64
26t 26t
0.36
t t
26.16
Forecast for month 9, ( D
ˆ
t+1
).
:5 :5
25.80
Expected usage for current
(month 8) period, (Smoothed
D
t
).
:0 :0
0.25
α
:2
:3
:6
:2
:3
:6
24.71
0.36
26.16
Record for initial values when
month 9 actual figures become
available.
Note: At least 4 periods of current data should be entered before forecasting is attempted.