CU HI V BI TP CHNG I 1.Nghin cu kinh t lng v nghin cu kinh t c g khc nhau v ging nhau? 2.Bn hiu th no v vai tr ca Kinh t lng trong vic ra quyt nh trong kinh t v kinh doanh? 3. thc y nhu cu s dng my mc trong sn xut nng nghip, lnh o tnh mun tm hiu xem cn tc ng bng cc chnh sch no? Nu bn l cn b S nng nghip, s dng 8 bc nghin cu trong Kinh t lng, bn s lm th no lm cn c xut ti lnh o ca mnh v vn ny. 4.Hin nay, Chnh ph Vit Nam khuyn khch cc doanh nghip trong nc u t ra nc ngoi, nu c t vn v quyt nh u t ra nc ngoi ca doanh nghip, bn s la chn nhng yu t no xem xt? CU HI V BI TP CHNG IV 1)Ti sao phi xy dng m hnh hi qui? 2)Phn tch hi qui c phi l phn tch mi quan h nhn qu? 3)Hy phn bit m hnh hi qui tng th; m hnh hi qui tng th ngu nhin; m hnh hi qui mu v m hnh hi qui mu ngu nhin? 4)Nhng s liu no c s dng trong phn tch hi qui? 5)S khc nhau ca phn d ei v sai s ngu nhin ui? 6)Trong cc m hnh sau, hy xc nh m hnh no l m hnh hi quy tuyn tnh tham s, bin s hoc c hai? +Yi=B1 + B2Xi + ui

+Yi=B1 + B2(Xi)2 + ui

+Yi=B1 + (B2Xi)2 + ui

+Yi=B1 + B2ln(Xi) + ui

+ln(Yi)

=B1 + B2Xi + ui

+Yi=B1 + B22Xi + ui

+Yi 2 =B1 + B2iX + ui

+Yi=B1 - B2 ||.|

\|iX1+ ui

7)Cc m hnh sau c l m hnh hi quy tuyn tnh hay khng? Ti sao? +Yi = i iu X B Be+ +2 1 +Yi = i iu X B Be+ ++2 111 +lnYi = B1 + B2 ||.|

\|iX1 + ui

+Yi = B1 + (2 B1) iX Be2+ ui

Yi = 1 21i iB B X u + + 8)Hy nu nhng gi thit ca phng php c lng OLS?9)Nu sai s ui khng tun theo phn phi chun th c th c lng c cc tham s bj khng? Gii thch? 10)Hy gii thch ngha ca cc tham s c lng t phng php OLS? Phng sai ca cc tham s c lng? Sai s chun ca cc tham s c lng? 11)Hy gii thch tng bnh phng cc bin ng ca bin ph thuc (TSS) l g? ESS l g? RSS l g? H s xc nh ? 12)Nu h s R2 = 1 th ta c kt lun g?+Bin X v bin Y bin i cng chiu v bng nhau ;+Bin c lp v bin ph thuc bin i nh nhau ;+M hnh co gin n v ;+Cc bin c lp trong m hnh gii thch hon ton (100%) s bin ng ca cc bin ph thuc ; +Tt c cc cu trn u sai. 13)Hy nu kim nh t, kim nh F trong phn tch hi qui? 14)Hy gii thch cc mnh sau ng hay sai? +Vi mc ngha thng k o v bc t do cho trc, gi tr tuyt i ca t(tk(bj)) ln hn gi tr t tra bng (tc), gi thuyt khng (H0) khng th bc b? +H s tng quan (r) c du ging nh du ca tham s b1 (hi qui gin n)? +Nu ui tun theo phn phi chun th b0 v b1 cng tun theo phn phi chun? 15)Nu c m hnh sau: Nng sut la = B1 + B2 (Mc bn phn ha hc) + u Hy cho bit trong trng hp nyB1, B2 v u l g? Nu m hnh l : Tin lng = B1 + B2 (Trnh hc vn) + u Th B1, B2 v u trong trng hp ny l g? 16)Mi quan h gia chi ph cho lng thc, thc phm (LT, TP) ca h v s ngi trong h nh sau (s liu mang tnh gi nh) S ngi/hChi ph cho LT, TP(tr. ng) S ngi/hChi ph cho LT, TP(tr. ng) XYXY 39,9311,1 610,447,4 515,149,4 612,9511,9 614,239,1 Nu mt ngi xy dng m hnh:Y = B1 + B2 X + u Hy c lng cc tham s B1 v B2? V th cc phn d? c lng phng sai v sai s chun ca cc tham s c lng? Tnh tng bnh phng bin ng ca bin ph thuc (TSS), (ESS) v phn d (RSS), h s xc nh hiu chnh? Tnh gi tr F? Gi tr ny c ngha thng k hay khng? Tnh khong tin cy cho tham s B1 v B2 vi mc ngha thng k o = 5%? C ngi kt lun rng s ngi trong h c tng quan vi chi ph cho LT, TP ca h vi mc ngha thng k 5%? Bn c ng hay khng? Hy gii thch? Nu nh m hnh by gi l:Ln(Y) = B1 + B2 Ln(X) + u th cc cu tr li trn y c thay i khng? Gii thch? 17) Gi s c m hnh sau: Log(Nng sut la) =B1 + B2 Log(X) + u;trong : Log l logarith; Nng sut la c tnh l t/ha; X l chi ph lao ng (ngy-cng/ha). Nu nh n v tnh ca Nng sut la by gi l kg/ha th cc tham s B1 v B2 c lng c s thay i th no? Gii thch? 18)C hm tiu dng nh sau: Yi =B1 + B2 Xi + ui . Trong : Yi l mc tiu dng ca h, Xi l thu nhp ca h. Xu hng tiu dng trung bnh (APC, Average Propensity to Consume) n gin c tnh l mc tiu dng bnh qun ca 1 n v thu nhp (Yi/Xi). T s liu iu tra 100 h nng dn v thu nhp v tiu dng (n v tnh l 1000 ng), ngi ta c lng c m hnh sau: = - 124.84 + 0,853 Xivi n = 100 v R2 = 0,692. (i)Hy phn tch hng s hay h s chn (intercept) v du v ln? (ii)Mc tiu dng ca h l bao nhiu nu thu nhp ca h l 25 triu ng? (iii)Hy v th v MPC v APC vi trc honh l Xi (mc thu nhp ca h)? 19)Vonm1983,cngtyVideoBoardTests,Inc.,mtcngtynghincuqungcoti New York tin hnh iu tra hng nm vi 20.000 ngi trng thnh v chng trnh qung co thng mi trn truyn hnh no m h tng xem, h ch v h a thch. Nhngntnglulivnidungqungcodatrncucphngvn4000ngi trngthnh,trongnhngkhchhngthngxuyncyucuklimtqung co v loi sn phm m h mi xem trong tun trc.S liu c s dng y da trn kho st 21 hng v cng c cng b trn Tp ch Ph Wall (the WallStreet Journal) nm 1984 .FIRM SPENDMILIMP MILLER LITE 50.1 32.1 PEPSI74.1 99.6 STROH'S 19.3 11.7 FED'L EXPRESS22.9 21.9 BURGER KING82.4 60.8 COCO-COLA40.1 78.6 MC DONALD'S185.9 92.4 MCI 26.9 50.7 DIET COLA20.4 21.4 FORD 166.2 40.1 FIRM SPENDMILIMP LEVI'S 27.0 40.8 BUD LITE 45.6 10.4 ATT/BELL 154.9 88.9 CALVIN KLEIN5.0 12.0 WENDY'S 49.7 29.2 POLAROID 26.9 38.0 SHASTA5.7 10.0 MEOW MIX 7.6 12.3 OSCAR MEYER9.2 23.4 CREST 32.4 71.1 KIBBLES 'N BITS6.1 4.4 Ngun: http://lib.stat.cmu.edu/DASL/Datafiles/tvadsdat.html Trong : FIRM l tn hng; SPEND l ngn sch qung co truyn hnh nm 1983 (tnh bng triu USD); MILIMP l hng triu n tng cn lu li tnh theo tun. Vy nu mun phn nh nh hng ca chi tiu cho qung co n n tng ca ngi khch hng th m hnh nn c xy dng nh th no? Anh (ch) phn tch nh th no v mi quan h ny? 20)C m hnh hi qui gin n: Yi =B1 + B2 Xi + ui . Nu B1 = 0 hay m hnh khng c h s chn (ng hi qui c lng i qua gc ta ). Hy: (i)c lng tham s b2 (l c lng ca B2)? (ii)Hy c lng phng sai v sai s chun ca b2? CU HI V BI TP CHNG V (1)Phn tch hi qui tuyn tnh gin n v a bin (nhiu bin) c g ging v khc nhau? (2)Trong tch hi qui tuyn tnh a bin (nhiu bin), gi thit no khc vi hi qui gin n? (3)c lng cc tham s bj bng phng php OLS liu c cn gi thit sai s ui tun theo phn phi chun? Ti sao? (4)Khi phn tch 1 tham s cn nu c ch tiu no? a. tin cy/mc ngha thng k ca tham s;b.Du ca tham s;c. ln ca tham s;d.Tt c cc p n trn u ng;e.Tt c cc cu trn u sai. (5)Trongvic c lng mt tham s thngk: a.Khongtin cy l 1 p; b.Xc sut ng l 1 - p ; c.Mc ngha thng k l 1 p;d. tin cy l 1 p; e.Tt c cc cu trn u sai. (6)Ti sao kinh t lng cn phi a ra h s xc nh hiu chnh, 2R ? (7)Trong 1 m hnh hi quy tuyn tnh, nu s quan st (n) cng t, s tham s (k) cng nhiu th s chnh lch gia R2 v 2Rcng ln, ng hay sai? Ti sao? (vi iu kin: n, k N v n > k) (8)C 2 m hnh nh sau: Yi = B1 + B2 Xi + B3 Xi2 + ui(a) VLog(Yi) = A1 + A2 Log(Xi) + A3 Log(Xi2) + ui (b) Trong : Yi = mc tiu dng v Xi = thu nhp ca ngi tiu dng. (i)Theo bn th cc m hnh trn c tha mn gi thit ca hi qui tuyn tnh a chiu? Ti sao? (ii)Hai m hnh trn c g ging v khc nhau? (iii) kim nh cc tham s Bj v Aj ta cn gi thit no? (iv)Mt ngi mun a thm bin ti sn ca ngi tiu dng (X2) vo 2 m hnh trn th h s xc nh ca 2 m hnh s tng hay gim? Ti sao? (v)Ti sao cc bj c lng t phng php OLS l cc c lng BLUE? (9)Gi s c ngi s dng m hnh sau nghin cu mi quan h gia thi gian ng, thi gian lm vic v cc yu t nh hng n lng thi gian dnh cho ng. Y = B1 + B2 X2 + B3 X3 + B4 X4 + u Trong :Y = Thi gian ng (gi/thng) X2 = thi gian lm vic (gi/thng) X3 = S nm i hc (nm) X4 = Tui (nm) (i)Nu nhng ngi tui lao ng mun nh i gia ng v lm vic th du ca tham s c lng B2 s nh th no? (ii)Bn c suy ngh g v du ca cc tham s B3 v B4? (iii)Gi s kt qu c lng l:Y= 232,55 + 0,148 X2 + 11,13 X3 + 2,20 X4 n = 700; R2 = 0,272 Nu ngi no lm vic thm 20 gi/thng, vy thi gian ng ca ngi s gim xung bao nhiu? Liu y c phi l s nh i? (iv)Hy phn tch du v ln ca X3? (v)Liu c th khng nh thi gian lm vic, s nm i hc, v tui gii thch phn ln bin ng ca thi gian ng? Nhng yu t no nh hng n thi gian ng? Liu X3 v X4 c tng quan vi X2? (vi)Nu m hnh l dng Log Log c 2 v th kt qu c g khc nhau? (10)Kt qu c lng hm cu bia ru mt nc Ty u nh sau: = - 0,014 - 0,354 X2t + 0,0018 X3t + 0,657 X4t + 0,0059 X5t

Se (0,012) (0,2688) (0,0005) (0,266)(0,0034) tk(-1,16)(1,32) (3,39) (2,47) (1,73) R2 = 0,689; n = 20 (nm). Trong : Y = Mc thay i hng nm v tiu dng bia, ru bnh qun u ngi (ch tnh ngi ln);X2 = Mc thay i hng nm v ch s gi thc ca ru;X3 = Mc thay i hng nm v ch s gi thc ca thu nhp kh dng bnh qun u ngi;X4 = S c s kinh doanh ru c cp php thay i hng nmbnh qun u ngi (tnh ngi ln); X5 = Mc thay i hng nm v chi tiu thc cho qung co bia ru bnh qun u ngi (tnh ngi ln). Ngun : Gujarati (1999). Yu cu : (i)Da vo l thuyt kinh t hy phn tch du ca cc tham s c lng? Lm th no kim nh c cc phn tch trn? (ii)Hy kim nh mc ngha ca cc tham s? (iii)Tnh khong tin cy cho cc tham s mc ngha 5%? (iv)Tnh gi tr F, 2Rv phn tch m hnh? (v)Hng s trong trng hp ny phn tch nh th no? (vi)Hy phn tch cc h s cn li? (11)C s liu ca 50h nng dn tnh H Ty (trch mt phn s liu t D n ACIAR ADP 1/1997/092) nh bng sau: Ho soYX1X2X3X4X5X6X7X8X9D1 1393,1010,7612,415,6956,9017,590227,4899,31 2498,0334,8529,5613,2421,6220,290239,5699,30 3552,2017,8833,4610,3833,4620,190287,8999,31 4372,4114,4810,3410,3439,3113,451,0390,5278,71 5545,7835,1714,4810,3427,9313,451,55105,8378,70 61333,3366,6761,1123,335,5664,440337,7831,60 7564,6439,3818,7514,0615,9420,630321,561110,50 8570,9234,2933,2113,9339,6426,250280,711110,51 9593,8832,8630,9513,3338,1020,240309,051110,51 10592,3232,9016,9411,8527,1022,26084,19911,70 11375,0019,0910,916,8247,7317,734,09210,0078,11 12515,3652,5016,5011,2556,2521,001,50293,2578,10 13540,0052,0018,0010,0050,0023,004,00293,0078,10 14519,1534,0017,006,0030,0016,502,00142,0056,00 15421,8820,6310,318,4442,1916,880296,7296,71 16683,7044,1211,9112,7925,5920,290340,1596,70 17489,6434,5032,6313,1339,0020,630354,7596,71 18324,009,6013,209,6048,0014,40096,0065,31 19543,7331,5014,6313,5030,0015,000,75106,3265,30 20584,8218,7520,0011,2531,2521,880221,88710,31 21617,0229,8219,9017,6925,1525,150233,96710,31 22577,7325,1531,769,2633,9718,53080,2979,01 23526,8032,5016,889,3835,0015,632,50126,0079,00 24351,4312,0010,296,8621,4317,14078,4342,51 25393,3343,5023,009,0036,0026,00065,6898,40 26393,3343,5022,928,9238,7520,83096,9298,40 27618,0540,2613,8911,059,8721,710238,031211,20 28629,2622,5012,129,8115,0020,190292,101211,21 29567,5323,0835,1921,3546,1520,190103,101210,71 30520,0237,5018,1614,8031,9716,781,97104,611210,70 31546,4322,5018,7513,1332,8126,250183,0086,91 32511,1324,7138,8215,0041,4724,260220,2486,91 33632,8922,0032,008,0040,0020,000103,2074,81 34595,3841,4715,4411,0329,5616,320121,2474,80 35520,0027,0016,008,0035,0015,0017,00233,0078,01 36575,8536,509,3811,4625,0015,632,50116,9688,60 37614,155,8615,910,000,0017,161,67476,2188,30 38653,4334,2231,590,0014,4815,801,32182,2888,31 39526,6133,9114,3512,3922,1718,914,5791,3088,30 40428,570,0011,790,000,0023,790172,93108,21 41611,140,0018,000,000,0026,700104,25108,20 42593,0113,4214,2111,845,9224,590105,00108,21 43553,7313,8028,5013,5036,0018,00097,8098,31 44440,7533,1617,765,9227,6317,371,5899,4798,30 45476,7921,8813,130,0025,0017,500167,2277,60 46538,5745,7110,365,0017,1423,570128,5777,61 47516,8340,7117,1415,7120,0015,710110,0054,60 48523,719,0014,250,0030,0030,7512,0080,85129,90 49709,8221,5623,4416,8839,3825,3115,0066,56129,91 50585,6044,7022,5010,5043,5015,750128,7098,21 Trong :Ho so = S th t h; Y = Nng sut qui i ra la ca cc cy trng (trn 1 cng thc lun canh ca cng mnh rung trong 1 nm) (kg/so/nm); X1 = chi ph ging (1000 /so/nm); X2 = Lng phn m bn (kg/so/nm); X3 = Lng phn kali bn (kg/so/nm); X4 = Lng phn ln bn (kg/so/nm); X5 = Lng lao ng gia nh s dng (ngy-ngi/so/nm); X6 = Lng lao ng thu (ngy-ngi/so/nm); X7 = Chi ph bng tin khc ngoi ging v phn ha hc (3 loi trn) (1000 /so/nm); X8 = S mnh rung m h c (s mnh/h); X9 = Din tch t canh tc ca h (so/h); D1 = 1, nu h trng cy lng thc (la, ng) trn mnh rung , D1 = 0, nu h trng cy khc. Yu cu: (i)Hy xy dng m hnh phn tch da trn nhng thng tin trn? (ii)Bng cc chng trnh m Bn bit (Regression trong bng tnh Excel; cc chng trnh thng k STATA, SAS,... v cc chng trnh kinh t lng SPSS, SHAZAM, EVIEWS, LIMDEP, MICROFIT, GRETL, ...) hy c lng m hnh xy dng? (iii)Phn tch cc kt qu? (12)Da trn s liu thng k ca cc tnh v ton quc (http://www.gso.gov.vn) mt s nm gn y (sau nm 1990), hy c lng m hnh sau : Mc tng trng GDP nng nghip = F (mc tng trng t nng nghip,mc tng trng lc lng lao ng, Mc gim ngho, C cu ngnh dch v trong nng nghip) (i)Hy xy dng m hnh kinh t lng phn nh mi quan h trn? Ti sao s dng dng hm ny? (ii)Da vo l thuyt kinh t hy phn tch du ca cc tham s cn c lng? Lm th no kim nh c cc phn tch ca Bn? (iii)Nu mun phn tch nh hng ca Lut Doanh nghip (2000) (mt trong nhng lut khuyn khch u t) cn lm th no? (iv)Hy c lng kt qu v phn tch kt qu? CU HI V BI TP CHNG VI 1)Khinoxuthinhintngacngtuyn?Phngsaicasaiskhcnhau?Ttng quan? 2)Khi phn tch cc hin tng kinh t phi cn c nhng gi thit no? Cho v d? 3)Th no l a cng tuyn? a cng tuyn gia 2 bin c lp v gia nhiu bin c g khc nhau? 4)C m hnh hm tng chi ph nh sau: TC = B1 + B2 q + B3 q2 + B4 q3 + u. Vi TC l tng chi ph; q l sn lng. M hnh trn c a cng tuyn hay khng? a cng tuyn hon ho hay khng hon ho? Bn c nhn xt g? 5)Cmhnh:Yt=B1+B2Xt+B3Xt-1+B4Xt-2+B5Xt-3+ut.Trong:Yt = tiu dng thi gian t; X = tiu dng; t = thi gian. (a) Bn c cho rng m hnh trn c a cng tuyn khng? Ti sao? (b) Nu cu (a) l c th lm th no gii quyt? 6)Nhngnidungsaulhqucahintngphngsaicasaiskhcnhau?(nghay sai?, gii thch?) (i) Cc c lng t phng php OLS l cc c lng khng ph hp. (ii) Gi tr F khng tun theo phn phi Fisher. (iii) Cc c lng t phng php OLS khng cn l cc c lng tuyn tnh khng chch tt nht (BLUE). 7)C ngi s dng m hnh sau: Yi = B0 + B1 X1i + B2 X2i + B3 X3i + B4 X4i + ui Trong : Yi l lng bia tiu th ca ngi th i X1 = Thu nhp; X2 = gi bia; X3 = vn ha ngi tiu dng; X4 = gii tnh (nam/n); i = l ngi tiu dng (ung bia) th i E(u|X1, X2, X3, X4) = 0 Var(u|X1, X2, X3, X4) = o2 X12 . (i)Hy bin i m hnh sai s khng cn hin tng phng sai khng ng nht. (ii)C th cn cch no khc? 8)Phng php WLS s tt hn phng php OLS khi mt bin quan trng b b st. ng hay sai? Gii thch? 9)Gi s c s liu l thuyt nh sau: Mc tiu dng (Y)Thu nhp (X2)Vn (X3) 5030322 6035392 5540481 6560630 7080810 651001009 801201273 901251250 851301320 1001351390 951401425 1101601633 1151801876 1202002252 1402202201 1552402435 1502602686 (i)Hy c lng Y l hm s ca X2 v X3 bng phng php OLS? (ii)M hnh trn c a cng tuyn khng? Lm th no bit? (iii)c lng ring r Y l hm s ca X2 v Y l hm s ca X3. Nhng m hnh ny ni ln iu g? (iv)c lng X2 l hm s ca X3. M hnh ny cho bit iu g? (v)Nu nh c a cng tuyn, bn s b bt 1 bin c lp (X1 hoc X2).? Ti sao c v ti sao khng? (vi)Nu ch da vo kt qu OLS (gi s chy trn bng tnh Excel), c th khng nh a cng tuyn c khng? Gii thch? (vii)V th phn d? Hin tng phng sai ca sai s khc nhau c xy ra? (viii)HysdngcckimnhPark,Gleijer,GoldfeldvQuantkimnhsliu trn? (ix)Nu cc kim nh trn cho thy c hin tng phng sai ca sai s khc nhau th ta cn lm th no? 10)Khi xut hin AR(1), phng php no c th s dng c cc c lng tuyn tnh khng chch tt nht (BLUE)? 11)Kim nh t tng quan bng phng php Durbin-Watson cn c gi thit no? 12)Nhng hn ch ca ch tiu thng k d (DW, Durbin-Watson)? 13)Wooldridge (2003) s dng m hnhYt = B0 + B1 Xt + ut c lng ng Philip tnh. Trong Yt l t l lm pht; Xt l t l tht nghip. Da trn s liu ca M t 1948 n n 1996, kt qu c lng nh sau: t Y= 1,42+0,468 Xt Se(1,72)(0,289)v n = 49; R2 = 0,053, 2R= 0,033 Da trn cc kt qu hy phn tch? Liu c s cn bng gia lm pht v tht nghip? 14)Vi s liu trong bi 9 (Chng 4) v sn xut trng trt ca mt s h nng dn H Ty. Yu cu: +Hy xy dng m hnh v c lng m hnh phn nh mi quan h gia nng sut la qui i v cc yu t u vo sn xut +T kt qu c lng, theo bn c vn g xy ra? Ti sao? Cch khc phc th no? CU HI V BI TP CHNG VII 1)Nu tm tt: +Th no l bin nh tnh, cho v d? +Phng php phn tch phng sai (ANOVA) c phi cng tng t nh phn tch cc bin nh lng? +Bin gi nh hng n h s chn (im ct trc tung)? +Bin gi nh hng n h s gc? +Bin gio dc (trnh vn ha) khi no l nh lng, khi no l nh tnh? 2)Nu mun phn tch nh hng ca cc ma n cu v qun o th cn a vo m hnh bao nhiu bin gi? Gii thch? 3)Nu yu im ca m hnh xc sut tuyn tnh? 4)Ti sao m hnh xc sut tuyn tnh c nhiu nhc im, nhng mt s ngi vn s dng? 5)Cc m hnh Logit v Probit c nhng nhc im g? 6)Liu c vn g xy ra khi c lng m hnh sau: GNPt = B1 + B2 Mt + B3 Mt-1 +B4 (Mt - Mt-1) +ut Trong : GNPt = Tng sn phm quc dn vo nm t; Mt = Cung tin vo nm t; Mt-1 = Cung tin vo nm (t-1). 7)Gi s c m hnh:Yi = B1 + B2 Di + ui Nu gi tr ca bin gi Di khng phi l 0 v 1 m c thay th bng 0 v 2. iu g xy ra vi B2 v cc gi trSe(b2) v tk (b2)? 8)DatrnsliutngquvcucphcaMgiaiontqu1/1961nqu2/1977, Huang, Siegfried v Zardoshty c lng hm cu c ph nh sau: ( )tLn Y= 1,2789 0,1647 Ln(Pt) + 0,5115 Ln (It) + 0,1483 Ln (Pt) 0,0089 T tk (- 2,14) (1,23) (0,55)(- 3,36) -0,0961 D1t-0,1570 D2t-0,0097 D3t tk (- 3,74) (- 6,03)(- 0,37) R2 = 0,80 . Trong :Y = lng c ph tiu dng/u ngi; P = Gi so snh ca c ph vi gi nm 1967; I = Thu nhp kh dng theo gi nm 1967; P = Gi so snh ca ch vi gi nm 1967; T = Bin thi gian vi qu 1/1967 = 1 v qu 2/1977 = 66 D1 = 1 cho qu 1;D2 = 1 cho qu 2; v D3 = 1 cho qu 3. Ln = Logarith t nhin YU CU: (i)Hy phn tch h s ca P, I v P? (ii)Nhn xt v co gin gi ca cu c ph? (iii)C ph v ch l hng thay th hay b tr? (iv)Phn tch h s ca bin thi gian, T ? Xu hng tiu dng c ph gim hay tng? (v) co gin thu nhp ca cu c ph? Liu c th kim nh co gin l c nh (=1)? (vi)Bin gi trong trng hp ny biu hin g? (vii)Hy kim nh v phn tch cc bin gi? (viii)Ma no l ma ung nhiu c ph nht? Liu kt qu c thay i nu nh ta chn ma khc lm c s i chng? (ix)M hnh ny s dng bin gi nh hng n h s chn khc nhau.Gi thit y l g? (x)Nu nh khng c gi thit trn, m hnh cn phi thay i nh th no? (xi)Gi s Bn c y s liu, c th xy dng m hnh cu c ph khc? Hy nu c th m hnh v gii thch? 9)Nu c m hnh:Yi = B1 + B2 D2i + B3 D3i + B4 (D2i D3i )+ B5 Xi + ui

Trong : Yi = tin lng; Xi = s nm cng tc;D2i =1 nu l nam;D2i =0 nu l n; D3i =1 nu tt nghip i hc tr ln;D3i = 0, cc trng hp khc. (i)Bin (D2i D3i ) phn nh iu g? Gii thch h s B4 ? (ii)Hy tm E(Yi|D2 = 1, D3 = 1, Xi) v phn tch? (iii)Du ca cc tham s Bj s nh th no? 10)C bng s liu sau: Hs ChuynmnLao ng Din tch(m2) Ti sn cah (1000) H cvay tin 102404425281 212369630400 303376858200 402338416500 524241235601 624412812151 70432884501 82237369551 91226121500 1032505226700 1102300534200 12133396134801 130227248001 1412377051000 1514508815001 160366125000 1733474266471 1804457026600 193314020210701 2001393639601 2122500111001 22358856286700 2333490016720 2422930230000 2533686889001 2632577435501 2712192023701 284242481055000 Ngun: Trch mt phn s liu iu tra ti tnh H Ty nm 2000. D n ACIAR ADP 1/1997/092. Trong : Chuyn mn l lnh vc chuyn mn c o to ca ch h = 0, nu ch h khng c chuyn mn = 1, nu ch h chuyn mn ngn hn = 2, nu ch h chuyn mn s cp = 3, nu ch h chuyn mn trung cp = 4, nu ch h chuyn mn i hc hoc cao hn. Lao ng l s lao ng ca h (ngi); Din tch l din tch t canh tc ca h (m2); Ti sn ca h l tng gi tr ti ca h (c SX v tiu dng) (1000 ) H c vay tin: = 1, Nu h c vay tin (c ngn hng v bn b, ngi thn). = 0, Nu h khng vay tin. Hy s dng m hnh Logit phn tch cc yu t nh hng ti quyt nh vay tin ca h? (hng dn: C th s dng LIMDEP xem chng 7 hoc SPSS vo lnh Analyze Loglinear Logit).