Exploration and description /Estimation

Putting the results for the two scenarios together we get:

 

Dip-tank areas

           Population estimates

Sub-region

 Population Sample

Scenario 1

Scenario 2


Lobamba
13


4
24,403 ± 4,276
20,023 ± 5,327

Malandzela

 12

7

 24,884 ± 4,310 22,408 ± 3,324

Mayiwane

 20

15

 77,510 ± 6,960 66,038 ± 6,680

Mbabane

 28

20

 84,489 ± 9,996 73,841 ± 6,883

Ntfonjeni

 13 7 32,897 ± 4,421 23,462 ± 3,347

Piggs-Peak

 14 5 46,526 ± 6,555 27,008 ± 4,481

Total

100

58

 290,709 ± 15,740 232,780 ± 12,756

As all sub-regions are sampled there is no further sampling variation to add when calculating the standard error for the grand total. There is, therefore, no additional term to add to the formula for the sampling variance.

The standard error for the total population is thus the square root of the sum of variances for each sub-region. For scenario 1 this is:

√(4,2762 + 4,3102 + . . . + 6,5552) = 15,740.

Similarly the standard error for scenario 2 is 12,756.