Stratified random sampling, Applied Statistics

Assignment Help:

Stratified Random Sampling:

This method of sampling is used when the population is comprised of natural subdivision of units, The method consist in classifying the population units into a certain numbers of groups called strata. Then random samples are selected   independently from each group. The division of the population into strata is done in such a way that.

(1)   There is greater homogeneity within each group also  called stratum;

(2)   There is no over lapping in various strata or groups.

In practice geographical, sociological and economic characteristics are used for dividing the universe into different strata.  For example, if is desired to study the wage levels of workers in an industry, it would be better to classify all works into skilled and unskilled males and females categories and then select random simple   from each group  in the ratio to the size of that group  in population. The size of sample from each strata may either be proportional or disproportional to  the size of each.

(a)    Proportional Size: Under this a given percentage of items are selected from each stratum. For example in case of 50% selection there will be a selection of 5 to 10 units and 10 of20 units. Consisting of 10 and 20 units. This selection will be at random following any of the methods discussed earlier.

(b)   Disproportional Size: A disproportional selection may also be followed if different strata reveal different levels of within strata variability. Following the normal sampling rules, a larger sample is recommended if some sub strata reveal greater degree of variability with regard to a phenomenon relevant to the inquiry in comparison to the general lot.


Related Discussions:- Stratified random sampling

Small sample test for mean, If the sample size is less than 30, then we nee...

If the sample size is less than 30, then we need to make the assumption that X (the volume of liquid in any cup) is normally distributed. This forces    (the mean volume in the sam

Advantages of mode, Advantages By definition, mode is the most typic...

Advantages By definition, mode is the most typical or representative value of a distribution. Hence, when we talk of modal wage, modal size of shoe or modal size of family i

PERCENTAGES, CALCULATE THE PERCENTAGE OF REFUNDS EXPECTED TO EXCEED $1000 U...

CALCULATE THE PERCENTAGE OF REFUNDS EXPECTED TO EXCEED $1000 UNDER THE CURRENT WITHHOLDING GUIDELINES

Statistical process control, Statistical Process Control The variabilit...

Statistical Process Control The variability present in manufacturing process can either be eliminated completely or minimized to the extent possible. Eliminating the variabilit

Draw a network diagram for this problem, The project of building a backyard...

The project of building a backyard swimming pool consists of eight major activities and has to be completed within 19 weeks. The activities and related data are given in the follow

Compare the t interval with the bootstrap interval, Jocko's Garage has been...

Jocko's Garage has been accused of insurance fraud. Data on estimates made by Jocko and another garage were obtained for 10 damaged vehicles (available in 'jockogarage.txt'). Here

Poisson distribution, Poisson Distribution The poisson Distribution  wa...

Poisson Distribution The poisson Distribution  was discovered  by French mathematician simon  denis  poisson. It is a discrete probability distribution. Meaning : In bi

mathematical anxiety, A study was designed to investigate the effects of t...

A study was designed to investigate the effects of two variables - (1) a student's level of mathematical anxiety and (2) teaching method - on a student's achievement in a mathemati

Sdsad, Ask questionsadsadsadsadas#Minimum 100 words accepted#

Ask questionsadsadsadsadas#Minimum 100 words accepted#

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