Stratified sampling examples
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From this stratified population, we wish to take a sample of <math>n=10</math>, taking <math>n_1=4</math> from the first stratum and <math>n_2=n_3=3</math> from the other two strata. The stratum parametric means and variances are given in Table 1. | From this stratified population, we wish to take a sample of <math>n=10</math>, taking <math>n_1=4</math> from the first stratum and <math>n_2=n_3=3</math> from the other two strata. The stratum parametric means and variances are given in Table 1. | ||
| + | |||
| + | ====Table 1==== | ||
| + | Stratum parameters for the stratified example population. | ||
| + | |||
| + | <blockquote> | ||
| + | <div style="float:left; margin-right:2em"> | ||
| + | {| class="wikitable" | ||
| + | |- | ||
| + | !''Stratum'' | ||
| + | !''<math>N_h</math>'' | ||
| + | !''<math>n_h</math>'' | ||
| + | !''<math>\mu_h</math>'' | ||
| + | !''<math>\rho_h^2</math>'' | ||
| + | |- | ||
| + | |1 | ||
| + | |14 | ||
| + | |4 | ||
| + | |6.29 | ||
| + | |3.49 | ||
| + | |- | ||
| + | |2 | ||
| + | |8 | ||
| + | |3 | ||
| + | |10.13 | ||
| + | |4.86 | ||
| + | |- | ||
| + | |3 | ||
| + | |8 | ||
| + | |3 | ||
| + | |5.38 | ||
| + | |2.48 | ||
| + | |} | ||
| + | </div> | ||
| + | |||
Revision as of 18:28, 16 December 2010
Example 1
Imagine the example population of \(N=30\) elements be subdivided into three strata as in the figure on the right. Here, stratification has been done arbitrarily into three strata of size 14, 8 and 8.
From this stratified population, we wish to take a sample of \(n=10\), taking \(n_1=4\) from the first stratum and \(n_2=n_3=3\) from the other two strata. The stratum parametric means and variances are given in Table 1.
Table 1
Stratum parameters for the stratified example population.
Stratum \(N_h\) \(n_h\) \(\mu_h\) \(\rho_h^2\) 1 14 4 6.29 3.49 2 8 3 10.13 4.86 3 8 3 5.38 2.48
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