rapid assessment of drinking-water quality in the republic of tajikistan

Selection of sampling units or rayons by proportional weighting
Example: utility piped supply in broad area 1 (RRS & Dushanbe)
Clusters required: 9
Cluster size: 30
Total number: 526
Sampling interval: 58.4
Random number: 12
Proportional weighting table
(original)
Proportional weighting table
(consolidated) a
Map
no.
Rayon
RADWQ
number
Cumulative
number
Map
no.
Rayon or
geographical area
RADWQ
number
Cumulative
number
6 Dushanbe 240 240
3 Darband
1 Garm 9 249
8 Fayzabad
5 Gissar 37 286
7 Kofarnigan
46 46
2 Jirgital 21 307
10 Rogun
13 Tavildara
6 Leninskiy 73 380
10 Rogun 4 384 6 Dushanbe 240 286
7 Kofarnigan 24 408
1 Garm
4 Tursunzade 70 478
2 Jirgital
39 325
8 Fayzabad 12 490
11 Tajikabad
3 Darband 4 494
5 Gissar
9 Varzob 2 496
12 Shakhrinau
58 383
13 Tavildara 2 498
9 Varzob
11 Tajikabad 9 507 6 Leninskiy 73 456
12 Shakhrinau 19 526 4 Tursunzade 70 526
a
Data in the consolidated table were used to select the sampling units. Rayons in the original version of the table, in which the number
of supply zones was below the cluster size, were consolidated into one geographical area by merging with neighbouring rayons, to
give the consolidated version of the table. The order of rayons or geographical areas was set alphabetically in the consolidated version
of the table.
Cluster no. for
UPS in broad
area 1 a
Calculation for
proportional weighting
Rayon
Samples per
rayon
1 12 Darband/Tavildara/Rogun/Fayzabad/Kofarnigan 30
2 70.4 Dushanbe 30
3 128.9 Dushanbe 30
4 187.3 Dushanbe 30
5 245.8 Dushanbe 30
6 304.2 Garm/Jirgital/Tajikabad 30
7 362.7 Gissar/Varzob/Shakhrinau 30
8 421.1 Leninskiy 30
9 479.6 Tursunzade 13
a
UPS = utility piped supply.
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