ISS (Statistical Services) Statistics Paper III: Questions 33  37 of 96
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Question number: 33
» Sampling Techniques » Stratified Random Sampling
Appeared in Year: 2010
Describe in Detail
Explain the concept of stratification in stratified simple Random sampling. What is proportional and optimum allocation in stratified simple Random sampling? With usual notations show that: V () _{opt } < V () _{prop} < V () _{ran}
Explanation
Stratification:
Stratification means division into layers, classes or categories. Past or some other information related to the character under study may be used to divide the population into various groups. Then simple random sampling or systematic sampling is applied within each stratum.
The strata should be mutually exclusive and exhaustive:
Question number: 34
» Sampling Techniques » Cluster Sampling With SRS  IntraClass Correlation Coefficient
Appeared in Year: 2010
Describe in Detail
What is cluster sampling? In the case of cluster sampling for proportions, obtain an unbiased
Estimator of population proportion. Also, compute variance of your estimator.
Explanation
Cluster sampling:
Cluster sampling is a type of sampling method. In this method, the population is divided into separate groups, called clusters. Then, a simple random sample of clusters is selected from the population. Then analysis is done on the data from the obtained sampled clusters.
The samplings lead to
Question number: 35
» Sampling Techniques » Simple Random Sampling With and Without Replacement
Appeared in Year: 2011
Write in Short
Explain the concept of simple random/sampling with and without replacement. In a simple Random sampling, show that is an unbiased estimator of .
Question number: 36
» Applied Statistics » Index Numbers » Price Relatives and Quantity or Volume Relatives
Appeared in Year: 2011
Describe in Detail
Explain the errors in the measurement of price and quantity index number.
Explanation
All index numbers are affected by mainly three types of errors.

Formula error

Sampling error

Homogeneity error
Formula error:
There is no universally accepted index number formula that will measure the price or quantity changes excatly. Each formula in common use has its own defeat and consequently some error is
Question number: 37
» Sampling Techniques » Stratified Random Sampling
Appeared in Year: 2011
Describe in Detail
Let for a stratified random samplingwhereis constant, is thecost per unitin i^{th }stratum, is the mean square based on units.
Estimate the sample sizen under optimum allocation for fixed cost.
Explanation
Under optimum allocation, are obtained such that
(i) minimize the variance of the estimate for (a) fixed sample size n;
(i) var (is minimum for fixed n
(ii) var (is minimum for fixed total cost C
(iii) Total cost C is minimum for