# Formula List for Biostatistics

**Topics:**Arithmetic mean, Sample size, Normal distribution

**Pages:**8 (1316 words)

**Published:**December 15, 2010

----

(n-r)!

2)Combination----nCr = nPr = n!

----- ------- n r! r! (n-r)! 3)Summation-----∑ X i

i =1

n

4)Product--------Л Xi

i=1

5)Age specific fertility rate(Asfr)=No of live birth at specific age ------------------------------------- No of women to specific age group Asfr=∑

6)Total fertility rate(TFR)= ∑ Asfr *group of year

7)Gross Reproductive Rate( GRR) =TFR*(100)sex ratio

205 f 8)Net Reproduction Rate (NRR)= {Σ( Asfr * nSx)} * group of year

9)Life Table-

nLx= Persons year live in the Interval

lx = No.of person live at particular age

nqx = Proportion of person live at particular age nSx = nLx

l0 * group of year , where l0 =5,00,000

10)Crude Death Rate (CDR)= Σ (Pi)*(asdri) →Direct Standardisation Σ Pi Where Pi= Population age wise,

asdri = Age specific death rate in particular age

At population level, s

Standard Death rate = Σ Pi*asdri

s s Σ Pi Where ,P =Standard Population ,i=age group

_

11)Mean(arithmetic mean)( X )=

_ For Ungroup data Mean ( X )= Σ Xx=Character observe, ----- n=the no. of observation n

__ For Group data Mean ( X)= ΣfiXifi=frequency,

----- , xi=Mid point of the

Σfi interval Σfi( n)=the no.of observation 12)Median=

For Ungroup data Median=Average of the middle two value =a+b

-----

2

>First arrange all data in Ascending order-small value

Comes first & larger in the last.

>Find out middle data

For Group data Median= L +(N/2-F) * C L=the lower limit ------------- of the median

fclass

N=the total

no.of observation F= The no. of observations up to the Median class(cumulative frequency/observation) f=frequency/observation in the median class C=the interval of the median class

13)Population(P) Change=

P2009-P2008

P2009=P2008 + [Births-Deaths] + [Immigrants – Emmigrants] 14) “Table” is used to summerise the data.Information derived from it is a frequency or percentage. Diagramatic representation of data is—

1) Bar diagram- for discrete data & continuous data

For this no. of observation/frequency is always taken onY-axis ....

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