4 labaratoriya Iqtisodiyot modellarida vaqt qatorlari va ularning ahamiyati

Trend modeli (chiziqli va parabolikmodellar tahlili)
Chiziqli trend modelini ko‘rib chiqamiz:
Trend Analysis for Mashinalar soni
Trend Analysis for Y

Data Y
Length 20

NMissing 0
Fitted Trend Equation

Yt = 474,7 + 15,06?t

Accuracy Measures

MAPE 3,501

MAD 21,650
MSD 626,703
Forecasts

Period Forecast

21 791,012
22 806,073
23 821,135
24 836,196
Trend tenglamasi:
Y_t (mashinalar soni) = 474,7+15,06t
Xatoliklari:

MAPE	47,322
MAD	23,002
MSD	649,976

Grafigi:

Davr(hafta)	Bashorat
21	791,012
22	806,073
23	821,135
24	836,196

Endi parabolik trend modelini ko‘ramiz:

Trend Analysis

Data Y
Length 20

NMissing 0
Fitted Trend Equation

Yt = 497,4 + 8,86?t + 0,295?t^2

Accuracy Measures

MAPE 3,148

MAD 19,620
MSD 550,225
Forecasts

Period Forecast

21 813,740
22 835,295
23 857,440
24 880,176
Trend modeli tenglamasi:
Y_t (mashinalar soni) = 497,4 + 8,86t +0,295t²
Xatoliklari:

MAPE	19,793
MAD	15,654
MSE	389,058

Grafigi:

Davr(hafta)__Bashorat__21__813,740'>Davr(hafta)	Bashorat
21	813,740
22	835,295
23	857,440
24	880,176

Demak, parabolik modelimiz yordamida bashorat qilgan keyingi haftalardagi mashina savdosi miqdori chiziqli trend modelida qilingan bashoratimizga nisbatan aniqroq chiqar ekan,
Endi eksponensial trend modelini ko‘ramiz:
Trend Analysis for Y

Data Y
Length 20

NMissing 0
Fitted Trend Equation

Yt = 487,987 ? (1,02408^t)

Accuracy Measures

MAPE 3,187

MAD 19,804
MSD 562,959
Forecasts

Period Forecast

21 804,258
22 823,623
23 843,453
24 863,762


Trend Analysis Plot for Y

Trend modeli tenglamasi:

Y_t (O’z…,) = 487,987*(1,02408*t)
Xatoliklari:

MAPE	49,53
MAD	41,78
MSE	2164,11

Grafigi:

Davr(hafta)	Bashorat
21	804,258
22	823,623
23	843,453
24	863,762

Modellarni xatoliklar bo‘yicha solishtiramiz:

Model turi	MSD
chiziqli	649,976
parabolik	389,058
eksponensial o‘sish	2164,11

Parabolik model mavjud ma’lumotlarni eng aniq tasvirlaydi, chunki bu modelning standart og‘ishi (MSD) eng kichikdir, Ushbu vaqt qatorini tavsiflovchi trend tenglamasi:
Y_t (O’z…,) =487,987*(1,02408*t)