# Sampling Techniques-Stratified Random Sampling (ISS (Statistical Services) Statistics Paper III): Questions 1 - 5 of 8

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## Question number: 1

» Sampling Techniques » Stratified Random Sampling

Appeared in Year: 2015

### Describe in Detail

Explain the principles of forming strata and clusters. What are the difference between stratified sampling and clusters sampling?

### Explanation

The principles of forming strata for a population are summarized below:

(i) The strata should be non-overlapping and should together comprise the whole population.

(ii) The stratification of population should be done in such a way that strata are homogenous within themselves.

(iii) If the limit of precision for certain… (122 more words) …

## Question number: 2

» Sampling Techniques » Stratified Random Sampling

Appeared in Year: 2015

### Describe in Detail

What are the advantages of stratified sampling? Consider the allocation of sample size n _{i} of strata given by , where N _{i} is the stratum size, σ _{i} is the within stratum standard deviation of the ith stratum, (i = 1, 2, …, k) and δ real. Write down the expression for the where stands for the unbiased estimator of the population mean of the study variate y based on sample random sample without replacement in each stratum.

### Explanation

In this type of sampling method first the whole population is divided into homogeneous groups under certain criterion. There groups are termed as strata. Many advantage of stratified sampling can be summarized as follows.

(i) if the admissible error is given, small samples is needed which results into a cut… (190 more words) …

## Question number: 3

» Sampling Techniques » Stratified Random Sampling

Appeared in Year: 2009

### Write in Short

Explain the principle of stratification. How would you determine the best mode of stratification?

## Question number: 4

» 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:… (419 more words) …

## Question number: 5

» Sampling Techniques » Stratified Random Sampling

Appeared in Year: 2011

### Describe in Detail

Let for a stratified random samplingwhereis constant, is the-cost per unit-in 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… (174 more words) …