BI TP CUI K I/ Cc gi nh cn phi xem xt theo bi Lng chu nh hng ca gio dc v kinh nghim lm vic theo chiu hng thun, tc Kinh nghim c hiu ng tc ng bin gim dn, tc l nhng ngi c nhiu kinh l ngi i hc nhiu hn v ngi c kinh nghim lm vic nhiu hn s c lng cao hn. nghim th mc tng lng khi tng thm kinh nghim s t hn ngi c t kinh nghim hn. C s phn bit v mc lng gia nam v n trong th trng lao ng v nam ni chung c mc lng cao hn n. II/ Xy dng m hnh v gii thch cc thnh phn. Theo phng trnh (m hnh) Mincer nguyn gc (1974), ta c Ln (wage) = o + 1*school + 2 * exper + 3 * exper2 Tuy nhin, theo yu cu bi, ta kho st thm tc ng ca gii tnh n mc lng. Do , phng trnh s c dng sau: Ln (wage) = o + 1*school + 2 * exper + 3 * exper2 + 4 * male Trong : Wage: Exper: School: Male: mc lng theo gi (USD) s nm kinh nghim (nm) s nm i hc (nm) c gi tr 1 nu l nam gii Ln (wage): bin ph thuc m t phn trm thay i lng theo cc bin c lp

III/ Xy dng phng trnh ca m hnh hi quy v phn tch kt qu Bng m t s liuDescriptive Statistics exper N Range Minimum Maximum Mean Std. Deviation Variance 3296 17.00 1.00 18.00 8.0419 2.29086 5.248 male 3296 1.00 .00 1.00 .5240 .49950 .250 school 3296 13.00 3.00 16.00 11.6302 1.65711 2.746 Exper2 3296 323.00 1.00 324.00 69.9181 38.61073 1490.788 Ln.wage 3296 7.30 -2.57 4.73 1.5891 .62702 .393 Valid N (listwise) 3296

a/ Trc ht, chng ta cn kho st mi tng quan tuyn tnh gia cc bin thng qua bng Correlations

Correlations exper exper Pearson Correlation Sig. (2-tailed) N male Pearson Correlation Sig. (2-tailed) N school Pearson Correlation Sig. (2-tailed) N Ln.wage Pearson Correlation Sig. (2-tailed) N Exper2 Pearson Correlation Sig. (2-tailed) N 3296 .129**

male 1 .129**

school -.193**

Ln.wage .088**

Exper2 .975** .000 3296 .134** .000 3296 -.259** .000 3296 .061** .001

.000 3296 1

.000 3296 -.119**

.000 3296 .174**

.000 3296 -.193** .000 3296 .088** .000 3296 .975**

.000 3296 -.119** .000 3296 .174** .000 3296 .134**

.000 3296 .277** .000

3296 1

3296 .277** .000 3296 -.259**

3296 1

3296 .061**

3296 1

.000 3296

.000 3296

.000 3296

.001 3296 3296

**. Correlation is significant at the 0.01 level (2-tailed).

C th thy rng s tng quan gia bin ph thuc v cc bin c lp l kh thp. iu ny bc u cho thy cc bin ph thuc s gii thch rt t trong m hnh ny. Tuy nhin, ta cn phi chy m hnh hi qui kt lun chnh xc hn. S tng quan gia cc bin c lp vi nhau cng kh thp, cho thy nhiu kh nng s khng xy ra hin tng a cng tuyn. Tuy nhin, c mt lu l tng quan gia bn exper v exper2 l rt cao n gin v bin sau c xy dng t bin u. b/ Sau y, chng ta s nh gi ph hp v kim nh ph hp ca m hnh qua hai bng Model summary v ANOVAModel Summaryb Model 1 R .368a R Square .135 Adjusted R Square .134 Std. Error of the Estimate .58339 Durbin-Watson 1.884

a. Predictors: (Constant), school, male, exper, Exper2 b. Dependent Variable: Ln.wage

Vi kt qu ca R-square (0.135) v Adjust R-square (0.134) cho thy cc bin c lp trong m hnh ch c th gii thch rt thp cho bin ph thuc (13.5% hoc 13.4%) nh cp ban u. Vi b s liu chng ta ang kho st, kinh nghim, s nm i hc v gii tnh tc ng n mc lng l khng cao

ANOVAb Model 1 Regression Residual Total Sum of Squares 175.376 1120.087 1295.463 df 4 3291 3295 Mean Square 43.844 .340 F 128.821 Sig. .000a

a. Predictors: (Constant), school, male, exper, Exper2 b. Dependent Variable: Ln.wage

kim nh ph hp ca m hnh, kim nh gi thuyt Ho: 1= 2 = 3 = 4 = 0 Trong bng ANOVA, vi gi tr F ln (128) so vi gi tr ti hn ca mc ngha 5% v Sig. rt nh. Do , ta c th bc b gi thuyt Ho, m hnh hi qui tuyn tuyn bi ca chng ta l ph hp v c th s dng c. c/ n y, ta c th vit phng trnh hi quy bi theo bng Coefficients:Coefficientsa Unstandardized Model B 1 (Constant) exper male Exper2 school -.305 .059 .247 -.002 .120 Coefficients Std. Error .103 .021 .021 .001 .007 .215 .197 -.093 .318 Standardized Coefficients Beta -2.971 2.805 11.968 -1.198 18.116 .003 .005 .000 .231 .000 t Sig. 95.0% Confidence Interval for B Lower Bound -.507 .018 .206 -.004 .107 Upper Bound -.104 .100 .287 .001 .133

a. Dependent Variable: Ln.wage

Phng trnh gii thch s ph thuc ca thay i mc lng vo s nm i hc, kinh nghim v gii tnh c biu din nh sau: Ln (wage) = -0.305 + 0.12*school + 0.059*exper 0.002*exper2 + 0.247*male ( 1 ) Din gii m hnh: Gi s cc yu t khc khng i, nu s nm i hc (school) tng 1 n v th mc lng s tng 0.12%. Gi s cc yu t khc khng i, nu kinh nghim (exper) tng 1 n v th mc lng s tng 0.059% Nu i tng l nam (male = 1), phng trnh c dng: Ln (wage) = -0.058 + 0.12*school + 0.059*exper 0.002*exper2 Nu i tng l n (male = 0), phng trnh c dng: Ln (wage) = -0.305 + 0.12*school + 0.059*exper 0.002*exper2 Vi Sig. ca exper, male v school < 0.05, ta c th kt lun 1, 2, 4 c ngha thng k. Hai gi nh Lng chu nh hng ca gio dc v kinh nghim lm vic theo chiu hng

thun, tc l ngi i hc nhiu hn v ngi c kinh nghim lm vic nhiu hn s c lng cao hn v C s phn bit v mc lng gia nam v n trong th trng lao ng v nam ni chung c mc lng cao hn n l hon ton chnh xc. Tuy nhin, vi Sig (exper2) = 0.231 > 0.05, 3 khng c ngha thng k v chng ta cha th kt lun kinh nghim c hiu ng tc ng bin gim dn. d/ gii quyt vn trn, ta x l b s liu theo mt hng khc bng cch phn nhm s nm i hc (Nhm 1: 1 9; Nhm 2: 10 12; Nhm 3: 13 16). Ta c cc bng kt qu sau khi phn nhm nh sau:Model Summaryb Model R 1 .362a

Adjusted R R Square .131 Square .130

Std. Error of the Estimate .58497 Durbin-Watson 1.915

a. Predictors: (Constant), Schoolrange, male, exper, Exper2 b. Dependent Variable: Ln.wage ANOVAb Model 1 Regression Residual Total Sum of Squares 169.320 1126.143 1295.463 df 4 3291 3295 Mean Square 42.330 .342 F 123.703 Sig. .000a

a. Predictors: (Constant), Schoolrange, male, exper, Exper2 b. Dependent Variable: Ln.wage Coefficientsa Model Unstandardized Coefficients B 1 (Constant) exper male Exper2 Schoolrange .249 .085 .240 -.003 .349 Std. Error .089 .021 .021 .001 .020 .310 .191 -.189 .304 Standardized Coefficients Beta t 2.799 4.103 11.637 -2.474 17.570 Sig. .005 .000 .000 .013 .000 .046 .977 .045 .884 21.633 1.024 22.203 1.131 Collinearity Statistics Tolerance VIF

a. Dependent Variable: Ln.wage

Nh vy, sau khi phn nhm, m hnh vn ph hp v c th s dng vi mt cht bin i trong kh nng gii thch ca cc bin c lp i vi bin ph thuc l (13.1% - R-square hoc 13% - Adjusted R-square). Khi ny, phng trnh hi quy mi c biu din nh sau: Ln (wage) = 0.249 + 0.349*schoolrange + 0.085*exper 0.003*exper2 + 0.240*male ( 2 )

Vi Sig. (schoolrange, exper, exper2, male), 1, 2, 3, 4 u c ngha thng k. Do , ta c th kt lun Kinh nghim c hiu ng tc ng bin gim dn, tc l nhng ngi c nhiu kinh nghim th mc tng lng khi tng thm kinh nghim s t hn ngi c t kinh nghim hn