gia trj gia tang cua trang trai
Bien phu thuoc: Ln GTGT
Lu£n van tot nghiep — Do Thi Bich Loan
Bien He so hoi quy ^linh
He sd chan 12,47 13,57*** Ln CPHI 0,24 4,18*** Ln LD 0,47 3,64*** Ln DTICH 0,26 1,99* D QLY 0,13 2,13** R2 0,69 F 25,66
Xac suat cua F 1,3904 I E -10
Lu^n van to t nghiep —^ . 0 ^ — Do Thi Bich Loan
Hay viet dudi dang phirang trinh:
Ln GTGT = 12,47 + 0,24 Ln CPHI + 0,47 Ln LD + 0,26 Ln DTICH + 0,13 Ln D QLY (13,57)*** (4,18)*** (3,64)*** (1,99)* (2,13)**
Glii chic. ***: Co do tin cay d mure 99%, ** : Co do tin cay d mire 95%,
* : Co do tin cay 6 mtfc 90%.
Cac sd trong ngoac don la gia tri t do may tmh ra nham kiem dinh gia thiet ( H J cho r^ng he sd hoi quy a, cua bien sd X, tuong ung bang 0.
Vdi gia thiet:
H(): a, = a 2= a , =a4 = 0 (tat ca cac bien giai thich X, khong anh hudng gi tdi gia tri gia tang cua cac trang trai).
H , : cd it nhat 1 he sd a 0 (cd ft nhat 1 bien giai thfch X,co anh hudng tdi gia tri gia tang cua cac trang trai). ( i = 1,2,3,4 )
Ket qua chay ham tai bang 16 cho thay: ty sd F (Fisher) cua cac trang trai la 25,66 vdi muc xac suat 1.3904I E - 10. Vay H„ bi bac bd vdi do tin cay P=1 -
1.3904I E - 10 hay P >99,99%.
Tire cd ft nhat 1 bien cd anh hudng tdi gia trj gia tang cua cac trang trai. Ndi cach khac, phuong trinh hoi quy la cd y nghla phan tfch.
Mat khac, he sd xac dinh dieu chinh R2= 0,69. Tuc la 69% su bien dong
cua gia tri gia tang duoc giai thfch boi su tac dong cua cac bien giai thfch dugc bao gom trong loai hinh. Con lai 31% la cac nhan td khac ben ngoai loai hinh anh hudng tdi su bien dong cua chi tieu gia trj gia tang.
Bang 16 cho thay, giua gia trj gia tang va sd lao dong chmh trong trang trai cd mdi tuong quan thuan chat (***).
Khi sd lao dong chmh tang len 1%, vdi dieu kien cac nhan td khac khong doi thi gia tri gia tang se tang binh quan 0,47%. Neu lao dong chmh tang len 1 lao dong thi gia tri gia tang se tang len la:
A p d u n g c o n g thurc:
V MPPx, =
Trong do: MPPx,: San pham hien vat can bien cua x,. a, : Cac he so tuong quan,