phuong phap nghien cuu khoa hoc TrinhBayC6.ppt

7/28/2019 phuong phap nghien cuu khoa hoc TrinhBayC6.ppt

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6.16.1--Tai sao lai lay mau? Cac khai niemTai sao lai lay mau? Cac khai niem

c banc ban Trong mot cuoc bau c, ch mot phan nho c triTrong mot cuoc bau c, ch mot phan nho c tri

c hoi ve cac y nh bo phieu cua ho, ngay cac hoi ve cac y nh bo phieu cua ho, ngay cakhi s quan tam cuoi cung cua ngi tham do lakhi s quan tam cuoi cung cua ngi tham do la vivicc anh gia ket qua la chonanh gia ket qua la chon cucui cngi cng hoanhoan

tat ve nhng phieu hp le ung hotat ve nhng phieu hp le ung ho S dung thuat ng thong ke, moi c tri c goiS dung thuat ng thong ke, moi c tri c goi

lalan vn v, cac c tri thc te c tham do c, cac c tri thc te c tham do cgoi lagoi lamaumau va tap hp toan bo nhng ngi hpva tap hp toan bo nhng ngi hple cho bo phieu c goi lale cho bo phieu c goi latong thetong the(tong so)(tong so)

(population).(population).


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c ban (tt)c ban (tt) SS lala chonchon caccac ngng cc vienvien trongtrong baubau cc tongtong

thongthong coco thethe cc xemxem xetxet nhnhnhngnhng giagia trtrcuacuabienbien ngng cc

goigoi rangrang ngng cc vienvien nhannhan cc so so lnln caccacphieuphieu baubau trongtrong tongtong thethe (tong(tong so)so) lala motmot thamtham

soso ToanToan bobo quaqua trnhtrnh ee coco cc ketket quaqua bangbangcachcach naynay cc goigoi lalachonchon maumau..


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c ban (tt)c ban (tt) Trong ieu tra mc song dan c hang nam, MoiTrong ieu tra mc song dan c hang nam, Moi

ho tren a ban dan c laho tren a ban dan c lan v hon v ho Neu tien hanh ieu tra toan bo so ho se rat tonNeu tien hanh ieu tra toan bo so ho se rat ton

hp nho hn so tong, tap hp nho nay c goihp nho hn so tong, tap hp nho nay c goilalamaumau

So lng n v ho trong mau goi laSo lng n v ho trong mau goi lac hay kchc hay kchthc mauthc mau va thng c ky hieu la n, tong sova thng c ky hieu la n, tong soho dan c thng ky hieu la N.ho dan c thng ky hieu la N.


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6.26.2--Chon mau xac suat va chon mau phiChon mau xac suat va chon mau phi

xac suatxac suat ThietThiet keke chonchon maumau coco thethe chiachia thanhthanh haihai loailoai::

thietthiet keke chonchon maumau xacxac suatsuat vava thietthiet keke chonchonmaumau phiphi xacxac suatsuat

quanquan cuacua ngingi nghiennghien cucu MotMot soso chonchon maumau phiphi chnhchnh thcthc baobao gomgom:: ((11)) chonchon maumau thuanthuan tientien;; ((22)) chonchon maumau phanphan oanoan;; vava

((33)) chonchon maumau chch nhnh


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Chon mau thuan tienChon mau thuan tien

ChonChon maumau thuanthuan tien,tien, khongkhong cancan chuchu yy enen

tnhtnh aiai diendien mama chch chuchu yy enen tnhtnh thuanthuan tientienchocho ngingi nghiennghien cucu..

oc kinh doanh ma chung ta quen bietoc kinh doanh ma chung ta quen biet


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Chon mau phan oanChon mau phan oan ChonChon maumau phanphan oanoan lala ss phanphan oanoan cuacua nginginghiennghien cucu veve caccac nhomnhom aiai diendien ee chonchon soso

nn vv aiai diendien trongtrong tongtong soso cuacua caccac nhomnhom

phanphan oanoan nn giangian lala chungchung tata co co ganggang ee chonchon soso oioi

tngtng mama chungchung tata nghngh rangrang soso oioi tngtng oo coco

ee aa enen c oc o ongong ee ThTh du,du, ee nghiennghien cucu 33 loailoai doanhdoanh nghiepnghiep--khachkhach hanghang coco quyquy momo doanhdoanh nghiepnghiep theotheo mcmcln,ln, vava vava nho,nho, ngingi nghiennghien cucu sese chonchon rara 33nhomnhom doanhdoanh nghiepnghiep --khachkhach hanghang vava phanphan oanoanrangrang oo lala 33 nhomnhom aiai diendien chocho oioi tngtng khachkhachhanghang tngtng ngng vivi 33 loailoai quyquy momo doanhdoanh nghiepnghiep

ln,ln, vava vava nhonho


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Chon mau ch nhChon mau ch nh ChonChon maumau chch nhnh lala laylay theotheo tyty lele gangan ungung cuacua

caccac nhomnhom aiai diendien trongtrong tongtong thethe ChungChung tata coco thethe tintin chacchac rangrang coco motmot soso phanphan loailoai

caccac nhomnhom oioi tngtng naonao o,o, changchang hanhan nhnh caccaccongcong tyty nho,nho, caccac congcong tyty trungtrung bnhbnh vava caccac congcong tyty

vivi cungcung motmot tyty lele mama nono chiemchiem trongtrong tongtong thethe ThTh du,du, tongtong caccac oioi tngtng nghiennghien cucu lala 11..000000 congcong

ty,ty, trongtrong oo coco 600600 congcong tyty nho,nho, 300300 congcong tyty trungtrungbnhbnh vava 100100 congcong tyty lnln.. ViVi soso chonchon maumau chch nhnhlala 1010%% trentren tongtong the,the, nhnh vayvay soso congcong tyty nhonho cc

chonchon sese lala 6060 congcong ty,ty, congcong tyty trungtrung bnhbnh lala 3030 vavaconcon tt lnln lala 1010


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Chon mau phi xac suat (tt)Chon mau phi xac suat (tt)

ChonChon maumau phiphi xacxac suatsuat lala dede phacphac thaothao vava thcthchien,hien, nhngnhng coco thethe chocho ketket quaqua saisai lechlech batbat chapchap

ss phanphan oanoan cuacua chungchung tata nhnh thethe nao,nao, neuneuchungchung khongkhong aiai diendien chocho tongtong thethe HanHan che che chnhchnh cuacua chonchon maumau hihi xacxac suatsuat lala

chonchon maumau naynay khongkhong aa rara c c ss ee anhanh giagiaquyquy momo giaogiao ongong cuacua maumau vava saisai soso cc lnglng

ChonChon maumau phiphi xacxac suatsuat coco thethe apap dungdung chochonghiennghien cucu ss bobo hayhay ieuieu tratra th,th, ieuieu tratra lamlamroro cc ss caccac giagia thuyetthuyet..


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Chon mau xac suatChon mau xac suat

ChonChon maumau xacxac suatsuat lala dada vaovao lyly thuyetthuyet

xacxac suatsuat ee laylay maumau ngaungau nhiennhien CoCo motmot soso cachcach laylay maumau ngaungau nhiennhien oo ll::

((22)) laylay maumau ngaungau nhiennhien hehe thong,thong, vava ((33)) laylay maumau ngaungau nhiennhien phanphan tangtang..


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Lay mau ngau nhien n thuanLay mau ngau nhien n thuan LayLay maumau ngaungau nhiennhien nn thuanthuan lala cachcach laylay maumau

mama moimoi nn vv phanphan tt trongtrong tongtong thethe eueu coco cchoihoi ngangngang nhaunhau xuatxuat hienhien trongtrong maumau

tongtong the,the, tngtng ngng vivi moimoi so so aa cc anan nhnhchocho tngtng phanphan tt lala motmot nhannhan hieu,hieu, sausau oo tata

xaoxao trontron caccac nhannhan hieuhieu vava rutrut ngaungau nhiennhien theotheososo lnglng aa nhnh sese chocho tata motmot chonchon maumau ngaungaunhiennhien..


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TH DU CHON MAU NGAU NHIEN NTH DU CHON MAU NGAU NHIEN N

THUAN (tt)THUAN (tt) ((22)) XacXac nhnh concon soso sese cc chonchon lamlam phanphan tt

mau,mau, concon soso oo phaiphai lnln hnhn 00 vava nhonho hnhn tongtongthethe NN (trong(trong thth dudu cuacua chungchung tata lala 900900 hoachoac15001500 tctc concon soso thth tt ss dundun chocho caccac hanhan tt

sese tt 11 enen 900900 hoachoac tt 11 enen 15001500));; (3) So lng phan t c chon bang kch thc(3) So lng phan t c chon bang kch thc

mau. Neu kch thc mau n bang 10% tong the,mau. Neu kch thc mau n bang 10% tong the,theo th du cua chung ta n se la 90 hoac 150theo th du cua chung ta n se la 90 hoac 150cong ty;cong ty;


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TH DU CHON MAU NGAU NHIEN NTH DU CHON MAU NGAU NHIEN N

THUAN (tt)THUAN (tt) ((4)Tiep theo ta s dung chng trnh may tnh4)Tiep theo ta s dung chng trnh may tnh

e chon ngau nhien 90 hoac 150 phan t giae chon ngau nhien 90 hoac 150 phan t giacac so t 1cac so t 1--900 hoac t 1900 hoac t 1--1500. Chung ta co the1500. Chung ta co thes dung ba hoac bon cot tng ng vi so tongs dung ba hoac bon cot tng ng vi so tong

t e a ay t ang so ngau n ent e a ay t ang so ngau n en Nhn t tren xuong t mot iem bat au tuy y,Nhn t tren xuong t mot iem bat au tuy y,

ta liet ke toan bo nhng ch so nho hn 901ta liet ke toan bo nhng ch so nho hn 901

hoac nho hn 1501, am bao ieu kien ta chahoac nho hn 1501, am bao ieu kien ta chaliet ke trc o. Khi o bang liet ke se co 90liet ke trc o. Khi o bang liet ke se co 90hoac 150 con so, so mau cong ty c chon lahoac 150 con so, so mau cong ty c chon la

cong ty tng ng vi con so trong bang liet ke.cong ty tng ng vi con so trong bang liet ke.


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Lay mau co he thongLay mau co he thong

LayLay maumau coco hehe thongthong lala cachcach laylay maumau auau tientien lala

ngaungau nhiennhien sausau oo cc cachcach kk nn vv lailai chonchon motmotphanphan tt (con(con goigoi lala chonchon nhaynhay coc,coc, trongtrong oo kk lala

ThTh du,du, tata chonchon 9090 phanphan tt (cong(cong ty)ty) trongtrong tongtongsoso 900900 phanphan tt (cong(cong ty),ty), tyty lele laylay maumau khikhi oo sese

lala 9090//900900==11//1010.. NhNh vayvay khoangkhoang cachcach bcbc nhaynhaykk ==1010.. CacCac soso thth tt cuacua congcong tyty cc xepxep tt 11enen 900900.. ayay cancan phaiphai xacxac nhnh phanphan tt auau

tientien lala ngaungau nhiennhien..


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Lay mau co he thong (tt)Lay mau co he thong (tt) Co the co hai cach e xac nh phan t au tienCo the co hai cach e xac nh phan t au tien

ngau nhien.ngau nhien. Cach th nhatCach th nhat, la lay ngau nhien trong toan bo, la lay ngau nhien trong toan bo

,,900), sau o t phan t a c chon cong900), sau o t phan t a c chon congthem hoac tr i k ( trong th du cua chung ta lathem hoac tr i k ( trong th du cua chung ta la

tr i hoac cong them 10, k=10). Neu phan ttr i hoac cong them 10, k=10). Neu phan tngau nhien la 900 phai tr i 10, neu phan tngau nhien la 900 phai tr i 10, neu phan tau tien la 1 th cong them 10au tien la 1 th cong them 10


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Lay mau ngau nhien phan tangLay mau ngau nhien phan tang Lay mau ngau nhien phan tangLay mau ngau nhien phan tang la phan cac oila phan cac oi

tng nghien cu thanh cac nhom, tang theotng nghien cu thanh cac nhom, tang theo

cac ac tnh, sau o lay mau theo tang, nhomcac ac tnh, sau o lay mau theo tang, nhom Chang han phan nhom cay trong rng theo oChang han phan nhom cay trong rng theo otuoi e chon mau khao sat. Nh tang 1 gomtuoi e chon mau khao sat. Nh tang 1 gom

tong so cay tren tuo , tang gom tong sotong so cay tren tuo , tang gom tong socay t 50 tuoi en 100 tuoi, tang 3 gom tong socay t 50 tuoi en 100 tuoi, tang 3 gom tong socay di 50 tuoicay di 50 tuoi

Sau o ap dung phng phap chon mau ngauSau o ap dung phng phap chon mau ngaunhien n thuan cho moi tang. Cach chon maunhien n thuan cho moi tang. Cach chon maunay co o chnh xac cao va co the phan tch ketnay co o chnh xac cao va co the phan tch ket

qua theo cac tang so sanh s khac biet..qua theo cac tang so sanh s khac biet..


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6.36.3--Xac nh kch thc mauXac nh kch thc mau Kch thc mau c tang len, tren tong the seKch thc mau c tang len, tren tong the se

hoan thien chat lng ket qua thong kehoan thien chat lng ket qua thong ke

Neu muc ch cua ieu tra la c tnh tham soNeu muc ch cua ieu tra la c tnh tham socha biet, th chat lng cua ket qua la quan hecha biet, th chat lng cua ket qua la quan hen h ch vi kch thc cua sai so c tnh chon h ch vi kch thc cua sai so c tnh cho

phepphep Sai so c tnh bang gia tr tuyet oi cuaSai so c tnh bang gia tr tuyet oi cua

khoang cach biet gia thong so cha biet vakhoang cach biet gia thong so cha biet vathong so c tnh. Nhng khi tham so cha bietthong so c tnh. Nhng khi tham so cha bietth sai so c tnh cung la cha biet. V vay xacth sai so c tnh cung la cha biet. V vay xac

nh xac suat la can thiet.nh xac suat la can thiet.


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6.36.3--Xac nh kch thc mau (tt)Xac nh kch thc mau (tt) SaiSai soso chocho phepphep coco thethe tnhtnh bangbang %%,, vava thngthng

cc kyky hieuhieu lala vava oo tintin caycay chocho phepphep tnhtnhbangbang xacxac suatsuat PP

acac n an a toantoan ococ--t ongt ong ee ococ aa t nt n toantoancc bangbang tnhtnh kchkch thcthc maumau nn phuphu thuocthuoc vaovaoPPvava

ChangChang hanhan bangbang tnhtnh kchkch thcthc maumau theotheo 11 so sogiagia trtr cuacua PPvava didi ayay::


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p

0,85 0,90 0,95

0,05 207 270 384

0,04 323 422 600

0,03 375 755 1867


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6.36.3--Xac nh kch thc mau (tt)Xac nh kch thc mau (tt)

MotMot soso congcong thcthc tnhtnh cc maumau toitoi thieuthieu aacoco trongtrong nhieunhieu taitai lieulieu thongthong keke.. DiDi ayay

nn cc motmot congcong thcthc xacxac nhnh nn

2

..

TrongTrong oo pp lala tyty lele maumau dd kienkien chonchon nn11 soso vivitongtong soso (so(so lnglng tongtong thethe oioi tng)tng) N,N, p=np=n11/N/N;;q=q=11--pp ;; ZZ cc goigoi lala giagia trtr bienbien thienthien chuanchuancc tnhtnh sansan trongtrong bangbang ngng vivi oo tintin caycay PP..

pqNn

Z22

.

+

=


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6.36.3--Xac nh kch thc mau (tt)Xac nh kch thc mau (tt) Kch thc mau toi thieu theo cong thc tren laKch thc mau toi thieu theo cong thc tren la

ln nhat khi mau so la nho nhat va t so la caoln nhat khi mau so la nho nhat va t so la caonhat. Ta co the thay gia tr ln nhat cua tnhat. Ta co the thay gia tr ln nhat cua ttrong cong thc tren xuat hien khi p=q=1trong cong thc tren xuat hien khi p=q=1--p hayp hay

p=0,5, nh vay n se la:p=0,5, nh vay n se la:

(6.2)(6.2) ( )

22

25,05,015,0

=

=

ZZxn


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6.36.3--Xac nh kch thc mau (tt)Xac nh kch thc mau (tt) KhiKhi bietbiet ==00,,11,, oo tintin caycay hayhay xacxac suatsuat P=P=00,,99,,

khikhi oo tratra bangbang coco giagia trtr bienbien thienthien chuanchuanZ=Z=22,,5858,, kchkch thcthc maumau toitoi thieuthieu cancan chonchonn=n=166166..

KhiKhi bietbiet quyquy momo tongtong thethe N,N, tata cungcung coco thethe xacxacnhnh kchkch thcthc maumau theotheo congcong thcthc sausau::

(6.3)(6.3)2

.

=

Zqpn


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Th duTh du::

XacXac nhnh kchkch thcthc maumau trongtrong ieuieu tratra mcmc

songsong dandan cc taitai motmot huyenhuyen coco 2525..000000 hoho dan,dan, vivisaisai soso chocho phepphep lala 11%%vava oo tintin caycay lala 9595%% CoCo motmot so so cachcach xacxac nh nh kchkch thcthc maumau trontron

thth dudu naynay:: CachCach thth nhatnhat:: TaTa khongkhong tnhtnh enen quyquy momo tongtong

thethe NN.. TraTra bangbang tnhtnh kchkch thcthc mau,mau, vivi==00,,0101;; p=p= 00,,9595,, tata coco n=n=99..603603..


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Th duTh du (tt)(tt) Cach th baCach th ba: Ta tnh en quy mo tong the N.: Ta tnh en quy mo tong the N.Khi o ta ieu tra tam tren so mau ban au nKhi o ta ieu tra tam tren so mau ban au n11==

7.500 ho gia nh, nh vay ty le mau d kien ban7.500 ho gia nh, nh vay ty le mau d kien ban

au se la 30% (7.500/25.000) hay p=0,3, khi oau se la 30% (7.500/25.000) hay p=0,3, khi oq=1q=1--0,3=0,70,3=0,7 Tra ban han bo chuan ta cun biet Z=1 96.Tra ban han bo chuan ta cun biet Z=1 96.

Van dung cong thc (6.3) vi cac thong soVan dung cong thc (6.3) vi cac thong so, q, p, q, pva Z se cho ta gia tr kch thc mau:va Z se cho ta gia tr kch thc mau: n= (25.000x1,96n= (25.000x1,9622x0,3x0,7)/(25.000x0,01x0,3x0,7)/(25.000x0,0122++

ZZ22x0,3x0,7)=6.093.x0,3x0,7)=6.093. Trong trng hp nay nTrong trng hp nay n11>> n, ta khong can tienn, ta khong can tien

hanh ieu tra them. Trong trng hp nhanh ieu tra them. Trong trng hp n11< n, ta< n, ta

phai tien hanh ieu tra them nphai tien hanh ieu tra them n--nn11 ho naho na


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33--Xac nh kch thc mau (tt)Xac nh kch thc mau (tt)

TrongTrong cachcach thth nhatnhat vava cachcach thth hai,hai, tata khongkhong

tnhtnh enen quyquy momo tongtong thethe vava coco soso maumau ln,ln, concontrongtrong cachcach thth ba,ba, tata tnhtnh enen quyquy momo tongtong thethe ,,

TuyTuy nhien,nhien, trongtrong trngtrng hphp quyquy momo tongtong thethe NNlnln hn,hn, caccac ketket quaqua veve kchkch thcthc maumau coco thethe

ngcngc lailai vivi ketket quaqua trentren..


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Cau hoi thao luan:Cau hoi thao luan:

11)) CacCac khaikhai niemniem cc banban veve mau,mau, kchkch thcthcmau,mau, cachcach xacxac nh?nh?

u nhuc iem va pham vi ap dung?u nhuc iem va pham vi ap dung? 3/ Hay ap dung mot trong cac cong thc tnh3/ Hay ap dung mot trong cac cong thc tnh

kch thc mau cho trng hp mot nghien cukch thc mau cho trng hp mot nghien cucu the cua bancu the cua ban


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BI TP 5:BI TP 5: (1) Xc nh i tng v s mu (kch cmu)(1) Xc nh i tng v s mu (kch cmu)

iu tra nghin cu vn t ra biiu tra nghin cu vn t ra bitrctrc--gii trnh cch xc nhgii trnh cch xc nh

cho vn nghin cu ca bncho vn nghin cu ca bn

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phuong phap nghien cuu khoa hoc TrinhBayC6.ppt