NHUNG NGHI6N CQU MOI TRONG KHOFI HOC KINH
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TS. Pham The Anh Dgi hoc Kinh te Quoc ddn
Bai viet nay nhim muc dich xac dinh cac nhan to quye't dinh lam phat a Viet Nam thdng qua mdt phuang phap tie'p can dan gian. Md hinh udc luqng cija chung tdi sCf dung CO sd ly thuyet ve lam phat cho mdt nen kinh te nhd va md. Cac kiem dinh ve s u tdn tai cCia cac md'i quan he dai han nhu dieu kien ngang bing sUc muaya can bing cCiathi trudng tien te cung duqc thuc hien de kiem tra kha nang anh hudng cOa chijng dep gia ca. Bai viet co ging dua mdt mdt vai gqi y than trqng cho chinh sach kiem che lam phat d Viet Nam trong giai doan thuc hien chinh sach kich ciu.
.^ . Co sd ly thuyet
Chunp tdi xay diing mpt mq hinh ly thuyet ddn g i l n ve cac nhan td xac djnh lam phat. Muc tieij chinh cda md iiinh nay la n h l m phan tich tac dpng cda cac bien sd khac nhau de'n lam phat d Viet Nam. Ve mat ly thuyet, lam phat cd the bj t i c dpng bdi nhieu yeu td khac nhau bao gdm'':
- Thang du cau ve hang hda va djch vu tQ khu viic tu nhan - Thang du cau ve cac nhan td san xuat
- Thang du lupng tien trong luu thdng dan den thang du tdng cau - Tham hut tai khda
- Cu sdc tQthe gidi ben ngoai I n h hudng den ti gia va xuat nhap khau
- Cac ye'u td thudc phia cung nhu nang s u i t lao ddng, chi phi dau vao va hanh vi thiet lap gia cua doanh nghiep
- Cac nhan td khac nhu chien tranh, cu sdc gia c l hang hda dau vao tren the gidi, sti kiem soat gia c l . Ngoai ra, cac yeu td phi kinh te khac nhu vai trd cda the che, mdi trudng chinh tri, van hda... cung cd the anh hudng den lam phat.
Tom lai, cac nha kinh te cd the chia cac nhanjd xac djnh lam phat thanh bdn nhdm chinh. ThQ nhat, dd la nhdm cac nhan td I n h hudng den tdng cau vi dij rihu thang ducung tien va tham hut taj khda. ThQ hai, dd la nhdm cac cu sdc thtic hay cu sd'c tdn^ cung yi dij ntnu sti mat gia cda ddng npi te, sti gia tang cda tien lUPng, lai suat, thue, va gj^a ca cac yeu td d i u vao. ThQ ba, do la nhdm cac yeu td I n h hudng den sti cQng nhlc cda gia c l vi dij nhu ki vpng, sii ciiam thay ddi cua gia c l va tien lUPng do hanh vi tliiet lap gia,... Va cudi ciing la nhdm cac yeu td the che.
Trong mdt nen kinh te thuc, lam phat cd the x l y ra do I n h hudng hdn hpp cda cac nhan td ke tren. Md hinh ly thuyet chung tdi trinh bay dUdi day chu yeu diia tren cac nghien cQu ve lam phat d cac nen kinh te chuyen ddi vi dtj nhuKim (2001) va Lissovolik (2003^. Do stihan che ve sd lieu phan anh cac cu sdc cung nhU tien lUdng, nang s u i t lao dpng, gia ca^cac yeu td dau vao, nen md hinh chung tdi xay dting d day chd yeu xem xet vai trd cac yeu td anh iludng de'n tdng cau.
Xuat phat diem cda md hinh nay chinh la md hln_h IS - LM chuan cho mpt nen kinh te nhd md.
Tat ca cac bien sd (trQ lai suit) deu dUpc bieu dien dudi dang logarit co sd tti nhien.
Ly thuye't^kinh te cho chung ta biet, tai mdt thdi diem bat ki, mQc gia chung cua nen kinh te (the hien qua chi sd gia tieu diing CPI) la trung binh cd trpng sd cda gia c l cac hang hda thuong mai (cd trao ddi vdi the gidi ben ngoai) va gia c l hang hda phi thuong mai (chi ban trong nudc).
A=^P'+0-^k" (-1)
trong d d p , la mQc gia chung, p', gia c l hang hda thQdng mai, p",gia c l hang hda phi thuong mai, va (/) la tl trpng cda hang hda thUdng mai trong gid hang tieu dung.
Gia c l hang hda thUdng mai cda mpt nen kinh^te nhd md dupc quyet djnh bdi thj trUdng the gidi va phu thupc vao gia c l d nudc ngoai, p', va ti gia hdi doai, e,. Su gia tang cua gia c l nudc ngoai va sti len gia cda ddng ndi te se dan den sU gia tang gia c l trong nudc do vay ta cd:
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HUNG NGHICN CUU MOI TRONG KHOfl HOC KINH T6
p', = p; + e, (2)
Gia c l cda hang hda phi thUdng mai phij thudc vao thi trUdng^ tien te trong nudc vdi^ gia djnh rang cau ve hang hda phi thUdng mai bien ddng cung chieu vdi tdng cau cua^nen kinh te. Do vay gia ca cda hang hda phi thUdng mai dUdc xac dinh bdi dieu kien can bang cua thi trUdng tien te, tQc la khi cung tien thtic te, (m^ - p), bang vdi cau tien thtic te, (m'^, - p):
P" = ^ ( ' " , - ( ' " , ' ' - P,)) (3)
trong dp A. la tham sd phan anh mdi quan he giQa tdng cau va cau ve hang hda phi thUdng mai.
Ham cau tien dupc xac dinh nhu sau:
m-l -p,=a + J3y,-rr, ^4^
trong dd /? va y lan lupt la he sd co dan cda cau tien thtic te theo thu nhap thtic te va Ipi tQc ky vpng. Thay phUdng trinh (4) vao phUdng trinh (3) chijng ta cd:
p" =A{m,-(a + fy,-\-yi;)) ^^^
Cudi cung, thay cac phUdng trinh (2) va (5) vao phUdng trinh (1) chijng ta thu dUdc ham phin anh mQc gia chung cda nen kinh te nhu sau:
P, =f("h'P! ')','>;^(^,)) (6)
PhUdng trinh nay cho chung ta thay mQc gia chung cda nen kinh te se phij thudc vao cung tien^
gia c l the gidi, thu nhap thtic te, lai suat va ti gia hdi doai. Cac bie'n tre cd the dUdc dUa vao de phan anh sii cham dieu chinh hay tinh cQng n h l c cda gia ca.
2. PhUdng phap Udc lUdng
De xac djnh cac nhan td quyet djnh lam phat trong m^d hinh thiic nghiem, chiJng td[ thiic hien theo cac budc sau: ThQ nhat, chung tdi thiic h|en viec kiem djnh tinh dQng cua cac chudi thdi gian sQ dung trong rnd hinh thtic nghiem. Cac chudi nay, trQ lai sua't, deu d dang logarit cd sd tti nhien va bao gdm chi sd gia tieu dung (Ip), tdng s i n pham qudc ndi (ly), cung tien rpng M2 (Im), ti gia hdi doai d^nh nghTa cda ddng USD tinh theo VND (lex), lai sijat tien gQi (r), va gia dau thd the gidi (loii). U day chung tdi sQ dung gia dau thd the gidi lam bie'n dai dien xap xi cho mQc gia the gidi. Neu cac chudi nay la khdng dQng (hay cd nghiem ddn vj), chung ta p^hli lay sai phan cho tdi khi nd cd tinh dQng trudc khi dUa vao md hinh thiic nghiem. GiQa cac chudi sd khdng dQng cd the tdn tai mdi quan he ddng tich hdp (mdi quan he trong dai han).
Budc hai, chung tdi sQdung phUdng phap phan tich ddng tich hpp cda Engle - Granger (1987) va Johansen (1990) nham xac djnh k h i nang tdn tai cac mdi quan he trong dai han giQa cac bie'n.
Vdi cac bien sd sQ dung trong mo hinh, chung tdi tap trung kierri tra hai mdi q^uan he dai han cd the cd trong md hinh do la: (i) mdi quan he giQa cac bien gia c l trong nUdc, ti gia, va gia ca tiie gidi (dieu kien ngang bang sQc mua - PPP) va; (ii) mdi quan he giQa cac bie'n tren thi trudng tien te bao gdm cung tien, gia c l , thu nhap va lai suat (dUdng LM).
Cudi cung, chung tdi se thiic hien khao sat mdi quan he dpng trong ngan han giQa lam phat va cac nhan td xac djnh nd. Md hinh dieu chinh sai sd (ECM) cd the dupc sQ dung ne'u tdn tai cac mdi quan he trong dai han ke tren.
2.1 Kiem dinh tinh dUng
Cac chuoi thdi gian chung tdi sQ dung trpng md hinh cd thdi gian tQ quy 1 nam 1995 den quy 4 nam 2008, thu thap t i i c a c ngudn nhuTong Cue Thdng Ke va Ngan Hang Nha Nudc. De kiem djnh tinh dQng cua chudi thdi gian chung tdi diia vao kiem djnh ADF (Augmented Dickey-Fuller) truyen thdng. Kiem djnh PP (Phillips Perqn) cGngdUdc tham khao de tang them tinh chinh xac ddi vdi ke't luan ve tinh dQng cda cac chudi. Dp tre trong kiem dinh ADF dupc liia chon diia tren cac chi' tieu AlC (Akaike Information Criterion) va SIC (Schwarz'information'Criterion). Ngoai ra, chung ta cd the thiic hienkiem djnh tti tUdng quan ddi vdi sai sd trong kiem djnh ve tinh dQng nham liia ehpn dupc dp tre hdp ly.
Ke't q u i kiem djnh tinh dQng trinh bay trong B l n g 1 cho tha'y bie'n lai sua't cd tinh dQng d mQc y nghTa 5% vdi c l hai loai kiem djnh ADF va PP. Ta't c l cac chudi sd cdn lai deu khdng dQng tham chi vdi sai phan bac nhat theo mua vu. Sai phan bac hai cda cac chudi nay cd tinh dQng d mQc
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NHUNG NGHtCN CUU MOI TRONG KHOR HOC KINH
#y nghTa 1%. Chung ta cd the ke't luan rang tat c l cac chudi sd, trQ lai suit, deu la tich hpp bac hai. 1(2). Sai phan theo mua vu cda cac chudi nay la tich hpp bac nhat, 1(1). Cdn sai phan bac hai cua chung la tich hdp bac khdng, 1(0), hay cd tinh dQng. Do vay, sai phan bac hai cua cac chudi sd nay se dUdc sQ dung trong md hinh xac djnh cac nhan td quye't dinh lam phat d Viet Nam.
2.2 Xac dinh cac md'i quan he trong dai han
Phan nay chung tdi sQ dtjng cac phUdng phap phan tich ddng tich hpp khac nhau de xac djnh mdi quan he trong dai han giQa cac bie'n sd dupc dii kien sQ ditng trong md hinh xac djnh lam phat 0 Viet Nam. Ne'u cac bie'n sd sQ dung trong md hinh cd mdt mdi lien he nao dd vdi nhau theo cac ly thuyet kinh te thi trong dai han chung se khdng di checti khdi mdi quan he nay. Vdi nhQng bie'n sd trong md hinh, hai mdi quan he dai han cd the cd ma chung tdi xem xet d day la mdi quan he ngang bang sQc mua va ham cau tien.
Ket q u i kiem djnh tinh du;ng cho thay sai phan bac nha't theo miia vu cda cac bien nay, ti;Q bie'n lai suit, la tich hop bac nhat. Do vay sai phan bac nhat se dUdc sQ dung de kiem dinh mdi quan he ddng tich hpp.
a. Dieu kien ngang bing sUc mua
Cac bien gia c l trong nudc, gia ca qudc te, va ti gia hdi doai cd the cd mdi quan he trqng dai han, hay cdn gpi la dieu kien ngang bang sQc mua. Do sti han che ve sd lieu ve ^ia tri xuat nhap khiau va tl gia tii cac thj tru'dng khac nhau tren the gidi nen chung tdi khdng the tinh dupc ti gia hdi doai hieu qua danh nghTa (nominal effective exchange rate). Bien ti gia chtJng tdi sQdtjng thay the d day la ti gia VND/USD. Ddng thdi, chung tdi cung diing bie'n gia d i u the gidi lam bien xap XI cho mQc gia c l the gidi.
Ke't q u i cua kiem dinh ddng tich hpp ddi vdi cac bien riay theo c l phuong phap Engle-
Granger va Johansen cho thay khdng cd mdi quan he ddng tich hpp giQa cac bien nay.' Do vay cd che dieu chinh sai sd (ecm) cua mdi quan he nay se khdng dudc dUa vao md hinh xac djnh cac nhan td quydt djnh lam phat.
b. Ham ciu tien
Cac bie'n tdng phUdng tien thanh toan, gia c l , thu nhap thtic te, va chi phi cd hdi cua viec giQ tien cd the cd mdi quan he vdi nhau trong dai han thdng qua ham cau tien. Ly thuyet kinh te cho chung ta bietrang sti gia tang cua thu nhap thtic te hoac sti giam sut cda chi phi co hdi cda viec giu tien se dan de'n sti gia tang cda c l u tien. Do vay, trong dai han cac bien sd nay khdng the tach rdi nhau, hay ndi each khac chung cd quan he ddng tich hdp.
Ket q u i kiem djnh ddng tich hpp theo phUPng phap Engle-Granger cho thay cd the tdn tai mdi quan he trong dai han giQa cac bien ke tren. Thdng ke kiem djnh PP cd y nghTa thdng ke d mQc 1%, trong khi dd thdng ke kiem djnh ADF cd y nghTa thdng ke d mQc 10%. Ben canh dd, ket q u i kiem dinh thep phUdng phap Johansen cho tha'y cd the cd tdi 3 mdi quan he ddng tich hpp giCfa cac bien sd tdng phuong tien thanh toan, gia c l , thu nhap thtic te, va lai suit. Cac co che tti dieu chinh se dupc dUa vao md hinh xac djnh lam phat, tuy nhien co che nao khdng cd y nghTa thdng ke sau dd se bj loai kholi md hinh.
2.3 Md hinh cac nhan td quyet dinh lam phat
Md hinh Udc lupng cac nhan td quye't djnh lam phat trong ngan han diia tren phuong trinh (6) dupc xac djnh nhu sau:
cl2/p = j3,^f^/S,d2lp,_,+f^/3„d2loil,_,+f^f^„cl2hu,_,
(7)
trong dd d2l chi sai phan bac^hai log cda^chi sd gia tieu diing (p), gia dau the gidi (oil), cung tien (mj, tl gia hdi doai (ex), va tdng s i n pham qudc npi {gdp): r la lai s u i t va; ecm la cP che dieu chmh sai sd. Neu cac tham sd a cda cac co che tii dieu chinh ecm cd y nghTa thdng ke thi phuong trinh nay ham y sti bien dpng lam phat khdng chi phu thupc vao cac nhan td nhu ham y trong phUPng trinh (6) ma cdn phu thudc vao tdc dp dieu chinh cda cac thj trudng ngoai hdi va thj trudng tien te.
3. Ke't qua Udc lUdng
Chung tdi gidi han dp tre tdi da cda cac bien d dp tre 8 (tUdng dUdng vdi 2 nSm) va thtic hien
kiiiliidliHliiii'n 31
^ 1 'HUNG NGHI6N CUU MOI TRONG KHOfl HOC KINH TC
udc lupng phUdng trinh^(7) theo^phUdng phap truyen tiidng. NhQng tham sd khdng cd y nghTa thd'ng ke se dupc loai bd dan khdi md hinh. Ke't qua cudi cting dupc trinh bay trong B l n g 2.
Md hinh gdm nhieu bie'n vdi cac dp tre khac nhau, hdn nQa cac bie'n sQ dung trong md hinh d dang sai phan bac hai nen viec dpc hieu ket qua Udc lupng khdng he de dang. Vi du bien phtj thudc d2lp cd nghTa la sUthay ddi cda ti le lam phat (tinh theo % thay ddi cda chi sd gia tieu diing so vdi cung ki nam trUdc) cda quy nay so vdi quy lien ke trUdc dd. Do s i i phQc tap nay nen chung tdi khdng di sau vao dpc hieu y nghTa cda tQng tham sd ma chi tap trung xac djnh xu hudng va dp tre I n h hudng cua cac bien ddc lap ddi vdi lam phat. Ket q u i trinh bay trong Bang 2 cho ta mpt sd ham y chung nhu sau:
ThQ nhat, ket q u i Udc lupng cho thay lam phat cda quy trudc cd I n h hudng Idn de'n lam phat hien tai. Dieu nay ham y sti ra tang lam phat d Viet Nam thudng keo dai lien tiep trong hai quy cd the do mdt sd nguyen nhan nhu: sti p h i n Qng cham tre cua cac chinh sach kiem che lam phat, tinh chat "dai d i n g " cda hanh vi tang gia, ki vpng thich nghi ve lam phat (tQc la, neu lam phat trong thdi ki trudc d mQc cao, cdng chijng se ki vpng mQc lam phat cao trong tUdng lai va gay ra lam phat). Lam phat d cac dp tre 2, 5 va 7 cung cd tUPng quan vdi lam phat hien tai nhUng theo chieu ngupc lai. Dieu nay cho thay khoing hai quy sau khi cd sti gia tang cda lam phat thi lam phat thudng cd xu hUdng g i l m khi nhQng chinh sach kiem che lam phat phat huy tac dtjng.
B l n g 2 cung cho thay lam phat trong nUdc trong thdi ki nay khdng chju anh hudng bdi sti thay ddi cda gia dau the gidi do chinh sach trd gia xang dau trong nUdc cua Viet Nam. Sti thay ddi cua tl gia cung cd nhQng chieu hUdng tac ddng trai chieu nhau va d nhQng dp tre khac nhau ddi vdi lam phat. Sti mat gia cua ddng ndi te so vdi ddng USD cd the lam gia hang nhap khau dat hdn va lam tang lam phat trong nudc. Tuy nhien, ne'u trong cung thdi gian dd ddng tien cda cac nUdc ma Viet Nam nhap khau mat gia nhieu hdn so vdi ddng USD thi mdi quan he tren cd the cd chieu ngUpc lai. Viec sQ dung ti gia hdi doai hieu qua danh nghTa (tQc la ti gia binh quan theo ti trpng thUPng mai tQ cac thj trUdng khac nhau) se cho ket q u i chinh xac hdn. Tuy nhien, sii han che ve sd lieu khdng cho phep chiing tdi thiic hien dieu dd.
Ket q u i quan trpng cda md hinh nay nam d tac dpng cua cac bien thupc chinh sach tien te.
Ket q u i udc lupng cho thay sii thay ddi cda cung tien cd tac manh den lam phat ke tQ quy thQ ba trd di sau khi thtic hien sti dieu chinh chinh sach. Do vay nhQng chinh sach md rdng cung tien va tin dtjng nham muc tieu kich c l u nhU hien nay can p h i i thtic hien vdi sti can trpng Idn va cd cai nhin dai han. Ngoai ra, ket qua ddi vdi bien lai suat cho thay sii p h i n Qng cham chap cda chinh sach tien te trong giai doan nay ddi vdi lam phat. Bien lai s u i t vdi dp tre 1 cd mdi quan he dUdng ddi vdi lam phat ham y sti p h i n Qng cda lai s u i t ddi vdi lam phat mang tinh thich Ung chQ khdng mang tinh chd ddng ngan chan. TQc la, khi lam phat x l y ra rdi thi lai s u i t dupc dieu chinh tang theo. Su gia tang cda lai s u i t chi cd tac ddng lam g i l m lam phat ke tQ quy thQ hai sau khi cd lam phat x l y ra. Ket qua nay rd rang cho thay cdng cu lai s u i t can dUpc sQ dung linh hoat va phin Qng nhanh nhay hon ddi vdi nhQng sQc ep lam phat nham ngan chan nhQng tac ddng tieu cUc cda nd ddi vdi nen kinh te. Cudi cung, dau dUdng cda cac tham sd di lien vdi bien gdp p h i n anh tac dpng cung chieu cda gdp, va do vay la tdng c l u , ddi vdi lam phat d cac dp tre khac nhau.
Cac kiem djnh sau Udc lupng cung dupc thtic hien nham d i m bao tinh hop ly cda md hinh. Ke't qua kiem dinh trinh bay trong Bang 3 cho thay md hinh khdng cd benh tiitUdng quan hay phUdng sai sai sd thay ddi. Nhin chung md hinh md t l kha td't sU bien dpng cda lam phat. Cac bien dpc lap cd the thich tdi 87% sii bien dpng cda lam phat trong ngan han.B
1. Tham khao bai bao cua Hendry (1999).
'' Ket q u a kiem dinh chi tiet se d u p c c u n g c a p ne'u b a n d o c c 6 y e u c a u . Tai lieu t h a m khao c h i n h :
1. Hendry, David F., "Does Money Determine UK Inflation over the Long Run?" In R. Backhouse and Salanti, A.
(Eds.), Macroeconomics and the Real World. Oxford: Oxford University Press, 2000.
2. Kim, Byung-Yeon, "Determinants of Inflation in Poland: a Structural Cointegration Approach." Discussion Papers No. 16. Helsinki: Bank of Finland, Institute for Economies in Transition, BOFIT, 2001.
3. Lissovolik, Bogdan, "Determinants of Inflation in a Transition Economy: the Case of Ukraine." Working Paper No.
03/126. Washington, D.C: IMF, June 2003.
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Kinhtp^PliHKriei
N H O N G NGHICN CUU M O I
TRONG KHOfl HOC KINH
#Bang 1: Ket qua kiem dinh tinh dirng Bien
so
Ip ly Im r lex loil dip dly dim dlex dioil d2p d2ly d2lm d2lex d2loil
Thong ke kiem dinh ADF AlC 1.46 0.19 0.33 -3,15' -3,32*
-1,45 -1,86 -2,14 -2,82
•1.84 -2.13 -2,72 -2,58 -3,47**
-5,38**
-4,00**
SIC 1,45
0.4 0,33 -3,15'
-1,59 -0,87 -2,86 -2,66 -3,57*
-1,84 -2,34 -4,35**
-7,25**
-5,72**
-5,38**
-4,70**
Thong ke kiem dinh PP
2,29 -4.13 0.33 -3,12*
-1,41 -0,99 -1,12 -2,66 -2,53 -2,46 -2,77 -3,86**
-7,28**
-5,72**
-5,15**
-3,99**
** cd y nghTa thong ke a mi/c 5% va 10%
Bang 2: <et qua Udc lucfng cac quyet dinh lam phat Bien phu thuoc: d2lp
Mau (dieu chinh):
Bien C d2lp(-1) d2lp(-2) d2lp(-5) d2lp(-7) d2oil(-4) d2oil(-5) d2lm(-3) d2lm(-4) d2lm(-5) d2lex(-2) d2lex(-7) r(-1) r(-2) d2lv(-2) d2ly(-4) d21y(-8) Adjusted R- squared F-statistic Prob(F-statistic)
1998Q2 2008Q4 Tham so -0.019
0.765 -0.515 -0.360 -0,298 -0.017 -0.025 0.137 0.151 -0.162 -0 223
0.469 0.008 -0.005 1.050 0.547 0.425 0.873 19.016 0.000
Sai sd chuan 0.008 0.106 0.112 0.124 0.109 0.007 0.009 0,038 0,042 0,042 0,087 0,079 0.001 0.001 0.218 0.268 0.219
nhan to
Gia tri p 0,030 0.000 0.000 0,008 0.011 0.032 0,011 0,001 0.001 0.001 0,016 0,000 0,000 0,002 0,000 0.052 0.063
Bang 3: Cac kiem djnh sau Udc lUdng Kiem dinh tu tucing quan Breusch-Godfrey LM:
hlo: Khdng co tu tuang quan F-statistic
Obs'R-SQuared
0,959 Prob, F(8.20) 12.855 Prob, Chi-Square(8)
0.496 0.117 Kiem djnh phuong sai sai so thay doi ARCH:
Ho: Khong co phuang sai sai so ttiay dot F-statistic
Obs*R-squared
0.692 Prob. F(8,26)
6.141 Prob.Chi-Square(8)
0,695 0.631
Hinh 1: Chuoi thdi gian - dang logarit
L C P I
••1 8 . 1 ' 6 -
11 2 1 1 0 - 1 0 8 1 0 6 10 4
('V • '
^rA/A^
y \ •
'\1 1 '
A./
'/
^5 96 97 98 ys 00 01 02 OJ 04 05 06 07 08 95 9b y7 ya 99 00 01 02 Oi 04 05 06 07 08
kinhicj'liiiilricn
33^ 1
H O M G N G H I C N CUU M O I T R O N GKHOfl HOC KINH T6
LM
95 96 97 98 99 00 01 02 03 04 05 06 07 0
L E X
95 96 97 98 99 00 01 02 03 04 05 06 07 08
LO IL
95 96 97 98 99 00 01 02 03 04 05 06 07 0 5 96 97 98 99 00 01 02 03 04 05 06 07 08
Hinh 2: Chuoi thdi gian - sai phan bac nha't theo mua v u
D L C PI D L Y
95 96 97 98 99 00 01 02 03 04 05 06 07 0
DLM
95 96 97 98 99 00 01 02 03 04 05 06 07 08 95 96 97 98 99 00 01 02 03 04 05 06 07 08
D L E X
95 96 97 98 99 00 Ot 02 03 04 05 06 07 0
34 l<'.J'liiill!*ipn
NHUMG NGHICN CUU MOI TRONG KHOfl HOC KINH m
Hinh 3: Chuoi thoi gian - sai phan bac hai
95 96 97 9fl 99 00 01 02 03 04 05 06 07 08 95 96 97 98 99 00 01 02 03 04 05 06 07 08
D2LM
95 96 97 96 99 00 01 0 2 03 04 05 06 07 0
D 2LE X D 2L0 IL
95 96 97 98 99 00 01 02 03 04 05 06 07 0
Hinh 4: Lam phat thiTc te, lam phat theo mo hinh va sai so
-.02 A » I ; I I
98 99 00 01 02 03 04 05 06 07 OJ
.08
R e s i d u a l Actual Fitted
