Stratified sample size - sampling size, Operation Research

Assignment Help:

Stratified Sample Size

The  sampling  study  has depended  much on the stratified sample  to reduce  the sampling  error, samples  size may have a number of strata or  clusters. The researcher   will have  to deal within  strata variability and within and between cluster variability in calculating the sample size. Since allocation of  the population members into  strata confines  each sub  samples  variance within the range of values in  each stratum the sampling error is  reduced to a very  nominal level the standard error has a  determined affect on the sample size. The stratified sample  size may  be  proportional of  disproportional. While  one stratum  may contain 0.55% of the  population size the other may contain  0.08% , 0.10% so on. The  percentage  may very as per requirements  and situations. In case of  stratified sampling only  the size  of the strum is used  as guide for allocating  the total  sample. The  size of stratified sampling may be  calculated as below :

     Ni = Ni /N -n

Where

 n = Number  of sample units  from stratum

Ni = total number  of units in  stratum

N= total number  of units  the population

n = sample  size  desired

the  advantage  of proportional  allocation  is that  it leads to an  estimate which is  computationally  simple. For calculation the  weighted  estimates, the  weighted calculation  of each  stratum is totalled.

Thus  standard  deviation of all the

 x st= √∑W3  ∑  i 2 / ni

Where  W i = weight of  stratum i = Ni/N

standard  deviation of the i stratum

The  disproportional stratified sample  may be a more desirable method if the standard deviation of the  observation in  each stratum  is known. Thus the standard  deviation of the mean of a disproportionate  stratified sample.

          σ =  σ √ ( W )2 / n

The cost per  observation  did not  enter  into the  formula for calculating the  sample  size  although cost  exerts a direct  impact. If the cost  per observation  or variability  is not  the same  for each  stratum there  is need  of determining  sample size by  considering  the precisions. Cost per  observation  b subgroup  is considered for  calculation  of sample  size.

 

 


Related Discussions:- Stratified sample size - sampling size

Graphic , max z 60x1+50x2 Sab to 4x1+10x2 2x1+2x2 3x...

max z 60x1+50x2 Sab to 4x1+10x2 2x1+2x2 3x1+2x2 X1+x2. >_ o

Scope., what is the scope of operational research in india ? explain with t...

what is the scope of operational research in india ? explain with the job names.

DECISION MODELS, CRITICAL EXAMINATION OF THE APPLICATION OF DECISION THEORY...

CRITICAL EXAMINATION OF THE APPLICATION OF DECISION THEORY TECHNIQUES OR MODEL IN BUSINESS DECISION MAKING IN NIGERIA

Simple graph-correlation and regression analysis, Simple Graph The val...

Simple Graph The values of the two variables are plotted on a graph paper. We get two curves one for x variables and another for y  variables. These  two curves reveal the dir

LINEAR PROGRAMMING, A paper mill produces two grades of paper viz., X and Y...

A paper mill produces two grades of paper viz., X and Y. Because of raw material restrictions, it cannot produce more than 400 tons of grade X paper and 300 tons of grade Y paper i

Transpotation problem, a manufacture wants to ship 8 loads of his product a...

a manufacture wants to ship 8 loads of his product as shown below. The matrix gives the mileage from origin to the destination D. Origin Destination Available A B C X 50 30 220

Usefulness of correlation - correlation regression analysis, Usefulness of ...

Usefulness of Correlation 1.Correlation  is very  useful  to economists  to study  the relationship  between  variables  like  price  and quantity  demanded. To businessmen it

Rank methods spearman s, Rank Methods Spearman s When the variables  u...

Rank Methods Spearman s When the variables  under  consideration are  not capable  of quantitative  measurement but can  be arranged  in serial  order( ranks) we find  correla

Linear programming model, Nass food produces to kinds of popular dark choco...

Nass food produces to kinds of popular dark chocolate bars. The banana and the coffee.the

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd