ktl de2
DESCRIPTION
kinh te vi moTRANSCRIPT
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BM01a/QT01/KT Cu 1: (7 im)
Cho bng s liu v lng sn phm bn c, gi bn sn phm v yu t khuyn mi ca
mt cng ty nh sau:
Y
8.2 8 8 7.9 7.8 7.6 7.5 7.7 7.4 7.6
X 3 3.2 3.4 3.5 3.6 3.8 3.9 4 4.2 4.5
Z
1 0 1 1 0 0 0 1 0 1
Trong :
- Y l lng sn phm bn c (triu sn phm/thng) - X l gi bn mt sn phm (chc ngn ng/sn phm) - Z=1: thng c khuyn mi v Z=0: thng khng c khuyn mi.
a. Vit hm hi qui mu ii
XY21
v cho bit ngha kinh t ca h s gc hi quy c. (2)
b. Tm h s xc nh v cho bit ngha ca n. (1)
c. Tm khong tin cy 99% cho h s gc 2. (1)
d. Mt nghin cu trong nm trc cho thy khi gi bn tng thm 10 ngn ng/sn phm th lng sn phm bn c trung bnh gim xung 800.000 sn phm/thng. Vi mc
ngha 1%, bn hy cho bit tnh hnh nm nay c thay i hay khng? (1)
e. Tm khong tin cy 99% cho lng sn phm bn c trung bnh khi gi bn ca mt sn phm l 37 ngn ng/sn phm? (1)
f. Vit hm hi quy mi vi n v ca Y l ngn sn phm/thng v n v ca X l ngn ng/sn phm? (1)
Cu 2 : (3 im) xc nh tc ng ca khuyn mi ln lng sn phm bn c, ta tin hnh chy m
hnh hi quy bi v thu c kt qu sau : 2
i ii . 0. 0 X 0. Z ; R 0.Y 9 419768 47 526. 191768. 932273
Se = (0.206175) (0.054393) (0.047531) 2R ? a. Vi mc ngha 5%, hy cho bit m hnh cu 2 c ph hp khng? Tnh h s xc
nh hiu chnh ca m hnh cu 2. C th ni m hnh cu 2 ph hp vi mu d
liu hn m hnh cu 1 khng? (1.5)
b. Nu ngha ca h s gc hi quy c ca bin Z. (0.5) c. Cho bit vi cng iu kin v khuyn mi, nu gi bn tng ln 10 ngn ng/sn
phm th lng sn phm bn c trung bnh thay i th no, vi tin cy l
98%?(1)
Cho cc gi tr : 0.005 0.01 0.05t (8) 3.355 ; t (7) 2.998 ; F (2;7) 4.74 Ch : - Cn b coi thi khng c gii thch g thm.