bài giảng thống kê y tế

C K .0 0 0 0 0 4 5 7 6 2

B

A

UXTNG CAN BO QUAN LY Y TE
BO MON THONG KE - TIN HQC

. I

G

I

A

N

G

A

THONG KE Y TE
(DUNG CHO BAC ST CHUYEN KHOA SAU DAI HQC
CHUY£ n NGANH Y TE CONG C0NG)

NHA XUAT BAN Y HOC
■ _ J

T R l/d N G CAN BO QUAN LY Y TE
Bo m on Thong ke - Tin hpc

Bai giang

THONG KE Y TE
DUNG CHO BAC SY CHUYEN KHOA SAU DAI HOC
CH UYEN NGANH Y T E CONG CONG

NHA XUAT BAN Y HOC
HA NOI - 1997


B a n bien soan:

T hacsl

: NGUYEN D l/C AN

B dcsl

: TRAN THI TUtJNG VY

B dc si

: TRAN THI LlTU

Cit n h a n :

PHAN VU D lfiM HANG

Ldl NOI DAU
Tap bai giang nay dugc bien soan voi muc tieu la trinh bay nhirng van de c a
s a cua Thong ke y te, diroc ung dung trong Nganh. Doi tirgng cua tap bai giang
chu yeu la cac hoc vien chuyen khoa cap mot cua Tnrong Can bo Quan ly Y te.
Nhirng bai giang nay da ft nhidu dugc Bo mon Thong ke dua vao giang day nhi6u
nam cho cac lop bac sy chuyen tu va chuyen khoa cap mot 6 trucmg nay. Vc noi
dung khoa hoc, cac bai giang dugc xem xet. sira chua va b6 sung ciin than; c a c vi
du va bai tap gSn ly luan vo'i thu'c ti6n cua Nganh Y te Viet Nam.
Noi dung cua tap bai giang nay dugc chia thanh ba phan:
• Phfin thir nhat: Thong ke mo ta.
• Phan thu hai: Suy luan thong ke.
• Ph^n thu' ba: Bo chi so thong ke y te co ban va phan loai thong ke
Quoc te benh tat Ian tlur X.
Tap bai giang gio'i thieu voi cac hgc vien cua Truong Can bo Quan ly Y te
co su tham khao cua cac tai lieu:
1. Betty R. Kirkwood. Essentials
Scientific Publications, 19S8

of

Medical

Statistics.

Blackwell

2. Phirong phap nghien cuu khoa hoc y hoc, Hoc vien quan y, Nha xuat ban
quan doi nhan dan, Ha Noi, 1995.

3. Dr. J.F . Osborn. Intensive Course in Medical Statistics. London School
o f Hygiene and Tropical Medicine. Centre for Population Studies,
Department o f Epidemiology and Population Sciences, 1991.
4. Phuong phap nghien cuu y te. To chii'c Y te The gioi, Khu vuc l ay Thai
Binh Duong, Manila, 1992. Vien Vc sinh Dich td hgc. Ha Noi, 1993.
5. PGS, PTS. Pham Huy DCing. Chi so y te cho tuyen co so' xa, phuong.
Khoa hgc y te cong cong Viet Nam, Truong dai hgc Y Ha Noi, 1990.
va mot so tai lieu khac.
Chung toi hy vgng rang voi noi dung nhu tren, tap bai giang nay co the: phu
hop voi cac hgc vien chuyen khoa cap mot, chuyen nghanh y te cong cong cua
Truong C B Q L Y T Ha Noi.
Vi kien thiic va kinh nghiem con han che, chac chdn rang tap bai giang nay
con nhi6u thieu sot. Chung toi rat mong nhan dugc nhung y kien phe binh va dong
gop cua ban trong va ngoai nganh de tap bai giang ngay cang chat lugng hon v6
n6i dung, phong phu hon vt hinh thuc, da dang hon v6 cac loai bai tap .

Xin chan thanh cam on.
Ha Noi, ngay I thdng 7 nam 7 9 9 7

Tran Thi Liru



THONG KE Y TE
MUC
TIEU MON HOC
•
•
♦

Trinh bay dudc cac so lieu nghien ctiu bAng bang thong ke, do thi, bieu do va
cac chi so thong ke thich hdp.

♦ Kiem dinh dtfdc so trung binh, so' titdng doi bang test t , x '

tieu chuan hoa .

♦ Danh gia dudc mol lien he tUdng quan gitia cac hien tadng nghien cCtu .
♦ Trinh bay dudc viec phan loai thong ke quoc te" cac benh tat (sUa doi lan thuf
mUdi) va cac qui tac hu6ng dan ma hoa tu vong .
♦ Phan tich dudc cac so lieu thong ke y te.
♦ Biet xay dung va to chiic cac nghien cCfu thong ke y te

NOIDUNG
Bai 1.
Bai 2.

Do thi, bieu do thong ke y te"

Bai 3.

Phep do vi tri va do bien thien

Cac phan phoi tan so

- Trung binh, trung vi, mode
- Do bien thien, phudng sai, do lech tieu chuan, he so bien thien

Bai 4.

Xac suat, cac luat phan phoi xac suat cua dai ludng ngau nhien
- Bien co* ngau nhien - khai niem xac suat
- Dinh nghla co dien ve xac suat, dinh nghia thong ke ve xac suat
- Phan loai sU kien ngau nhien
- Phan phoi nhi thtic, phan phoi poisson, phan phoi chu^n
- Lien he giuta ba luat phan phoi
- Ung dung va tAm quan trong cua phan phoi chu&n.

Bai 5. Cac phan phoi mau va cac khoang tin cay
Bai
Bai
Bai
Bai

6. Cac phep kiem dinh co y nghia
7. Kiem dinh gia thuyet thong ke
8. Lien he tUdng quan va hoi qui
9. Phudng phap tieu chuftn hoa
- Phudng phap true tiep
- Phudng phap gian tiep

Bai 10. Thong ke tinh hinh mac benh cua nhan dan
Bai 11. Bo chi so' thong ke y te cd ban
Phu luc. Phan loai thong ke quoc te cac benh tat va cac qui t&c hu6ng d^n ma hoa
tii vong.
1


GIClI THIEU
Thong ke y te la mot mon khoa hoc ting dung, ngUdi ta da svt dung cac

phudng phap thong ke y te vao cong tac nghien ctiu y te. No la mot trong nhQng
mon khoa hoc cd sd c&n thiet cho viec dieu tra, danh gia cac van de trong y te : Tit
sinh ly hoc te bao den nghien ciiu stic khoe cong dong...v.v.
Mac du tvf lau sinh hoc da ufng dung cac phudng phap cua khoa hoc thong ke
mot cach rong rai, nhung chi trong mot vai nam gan day, thong ke y te mdi thtfc sU
la van de noi com . Su dung thong ke y te doi hoi phai dudc dao tao kien thtic ca ve
toan hoc va y hoc.
Tuy nhien de hieu va ap dung dudc cac phudng phap thong ke cd ban doi hoi
phai biet mot it toan hoc dang ke . L6p hoc chuyen khoa mot cua TrUdng Can bo
Quan ly Y te khong can biet trudc kien thtic toan hoc hoac thong ke, ma mot it kien
thiic do neu ckn se dudc gi6i thieu trong qua trinh hoc tap.
Cac phudng phap thorig ke cd ban dudc chia thanh hai ph^n chinh : Trong
ph^n thti nhat chung ta co mot tap hdp so' lieu dudc quan sat va can tom tat chung,
xay dilng chung thanh cac bang qua do co the hieu dudc de dang va mo ta dudc
nhflng dac trUng cua chung. Cac phudng phap sik dung cho muc dich nay thUdng
dudc goi la thong ke mo ta.
NgUdc l a i , chung ta co the tong quat hoa cac thong tin tren m lu quan sat. Vi
du: Co the chung ta muon ket luan rang , nhin chung dung thuoc A tot hdn dung
thuoc B cho nhiing benh nhan co chan doan dac biet , vi vay chung ta phai sU dung
cac phep thu co y nghia va cac khoang tin cay. Cac phudng phap sU dung cho muc
dich nay dudc goi la phudng phap suy luan thong ke.
Cac nha nghien cilu sinh y hoc, cac bac sy lam cong tac quan ly y te va y
te cong cong , cac nha chilc trach c&n lam gi ? chdc r&ng ho c4n mot it thdi
gian de hoc nhflng tu tUdng cd ban cua thong ke , muc dich la hieu day du y
2

nghia, cach trinh bay va cac ky hieu thong ke nhu: p, t, X’ , r ... v.v. va cac
th u at ngiJ chuyen mon khac ma ho se tim thay trong cac bao cao cung nhvt
trong cac tap chi chuyen nganh.

2


B a i l . CAC PHAN PHOI TAN SO
MUC TIEU
Hoan thanh bai 1 hoc vien co the:
• Phan loai cac bien dinh tinh , dinh ltfdng, rdi rac, lien tuc
• Chia khoang bien thien cua mot day so' lieu thanh cac khoang cach to, va
chi ro cac gia tri nao nam d khoang cach to nao.
• Cho mot tap hdp lieu ban d&u, xay dung phan phoi t&n so ,t&n suat va tan
suat tich luy
• Ve bieu do phan phoi tin so' co khoang cach to blng nhau va khong bang nhau
• Ve bieu do tin suat tich luy, va xac dinh trung vi
Trong mot cuoc dieu tra thong ke, so' lieu thu th&p thudng chua dudc sap
xep, cho ta mot hinh anh hon don, kho nhin , kho rut ra qui luat cua hien tUdng
nghien ciiu.
De trinh bay cac ket qua nghien ciiu ngUdi ta thudng dung 3 hinh thtfc: bang,
do thi hoac cac tham so' dac trung. De bieu di§n cac so lieu ro hdn c&n s£p xep
chung theo thti tu, thudng tti nho den 16n. Nhu vay ta se thay dudc tinh chat phan
phoi va tinh quy luat cua chung, dong thdi cung biet dudc do bien thien do la hieu
so cua gia tri 16n nhat va gia tri nho nhat cua day.
Neu bang so' lieu chila toan bo day so' se rat kho nhin. Thong thudng ngUdi ta
tap hdp 2 hoac nhieu gia tri quan sat vao mot to.

1. Muc dich va y nghia cua phan to thong ke.
- La can ci'i vao mot hoac mot so' dac tinh de phan chia cac ddn vi cua hien
tUdng nghien ciiu thanh cac to co tinh chat khac nhau.
- La sap xep co he thong cac so lieu ban d&u de thay ro thanh ph&n, cd cau
nhutng net gio'ng nhau, khac nhau cua hien tUdng nghien ciiu.
- Bu6c d&u chuan bi cho tinh toan phan tich sau nay

2. Mot vai y nghia.
- To: La so lifdng cac gia tri quan sat nam trong mot gidi han nhat dinh.
- Gi6i han to: Do tri so' 16n nhat va tri so be nhat cua to tao nen.
- Tri so giuta: So' trung binh cong cua 2 gicfi han to.
3


- Khoang cach to (k) ( con ky hieu la h ,d ......) la tri so cua 2 tri so giCta lien
tiep nhau.

<

.

.

„

r

- To md: La to bao gom cac gia tri nam du6i hoac tren mot gia tri gidi han. Vi
du: Tren 100 tuoi, du<3i 18 tuoi.......

3. Dac tinh phan to ( con goi la dac tinh nghien ciifu).
Moi don vi nghien ciiu co nhving dac diem (dau hieu) noi len mat liidng hay
mat chat cua ddn vi do. Nhiing dac diem lien quan den muc dich nghien ciiu goi la
dac tinh nghien ciiu.
Co 2 loai dac tinh nghien ciiu:
a. Dac tinh dinh tinh:

La nhiing dac tinh nhan thiic bang giac quan. chung dac trifng cho chat
lUdng, co tinh ch a t mieu ta , dien dat bang ldi noi, chut viet (vi du: Gi6i tinh, loai
benh, nghe nghiep.......)

,

b. Dac tinh dinh-luc/ng:

La nhufng dac tinh bieu hien bang nhiing con so' nhu can nang , chieu cao,
huyet ap........ ) la nhiing dfic tfnh co the dem dudc hoac do dudc.

4. So to va khoang cach to.
Tuy tfnh chat cua dac tinh nghien ciiu va muc dich nghien ciiu.
a. Dac tinh dinh tinh:

Neu the hien bang 2 tinh huong (vi du gi6i tinh nam , mi) hai bieu hien doi
lap (dac tinh luan phien) thi chi co hai to.
Neu the hien bang nhieu tinh huong (vi du nhu ket qua dieu tri) thi co nhieu
to. Moi loai hinh la mot to hoac ghep nhieu to nho giong nhau thanh mot to 16n.
Tu: bang so lieu ban dau ta xay diing bang phan

Xi

n,

phoi thuc nghiem hay con goi la bang phan phoi tan so'

Xi

ni

gom 2 cot cd ban:

X,

n2

Xk

nk

Cong

In , = n

- Cot 1: Ghi cac dac tinh nghien ciiu ky hieu la
Xj neu la dac tinh dinh lUdng v6i i= l,2 ,3 ........ ,k
- Cot 2 : Ghi so' lan xuat hien dac tinh nghien ciiu,
con goi la tan so, ky hieu la n, (i= l,2 ,3 ............,k)

4


Tong so cac t in so" quan sat bang tong so ddn vi nghien ciiu (ky hieu la n)
Snj = n
(E : ky hieu cua tong )
b. D ac tinh d in h lUQng:
- Dac tinh dinh lufdng rdi rac : Bieu hien bang so" nguyen ( so" benh nhan, so cd
sd dieu tri....... ). Ta ghi cac gia tri x; theo chieu tang hoac giam din vao bang phan

phoi t in so, roi ghi tan so xuat hien cua moi gia tri x, (tiic la cac tin so n, . Khi sU
bien thien ve mat lildng giuta cac ddn vi it, co vai tri so, thi moi tri so hinh thanh
mot to (so con trong gia dinh)
Khi cac tri so bien thien nhieu, so to se qua nhieu, can phai phan to co
khoang cach to, bao gom mot pham vi cac gia tri : Co gi6i han du6i cua to la tri so"
nho nhat va gidi han tren cua to la tri so' 16n nhat cua to do. Neu mot gia tri rdi vao
gidi han tren va cung la gidi han dudi cua to sau thi quy udc xep vao to sau.
- Dac tinh dinh ltfdng lien tuc : Bieu hien bang so' nguyen, so' thap phan.
Thudng ta phan to co khoang cach to deu ( k = 1, 2, 3, 5, 10, 20......). De tien viec
tinh toan, khoang cach to nen la mot so le, de tri so' giiia la so nguyen.
Co the phan to v6i khoang cach to khong deu tuy muc dich nghien ciiu (vi du :
Bien tuoi trong dieu tra dan so...)
Phan to theo khoang cach to deu thi tri so khoang cach to dudc xac dinh theo
cong thiic :
X m —Xm

xM : Tri so' 16n nhat trong day so lieu.
xm : Tri so' nho nhat trong day so' lieu.
T

: So' to dii dinh chia

Nen chon cach phan to do'i xiing : Tri so' co tan so 16n nha't d g in giuta phan
phoi va khong co to trong (ns = 0 )
Phan nhoi tan so .
Ddn gian la mot bang ghi cac gia tri co the la'y bdi mot bien va ghi tan so ling
vdi moi gia tri da diidc quan sat.

5