Sample size The most frequently used formula to calculate the sample size is the following one, as it does not depend on the size of the total population. 2
N = D * Z * (p) * (1 – p) / c
2
Where: N= Sample size D = Design effect Z = The level of confidence desired p = Prevalence of our main indicator c = The standard error For a simple sampling, if we consider a prevalence of 50%, with a confidence level of 95% and a maximum error of 5.5%, the minimum sample size should be of 315 interviewed persons. But in case of a 2-stage sampling, our methodology, there is a design effect of 2, which brings the minimum sample size at 630 interviewed persons. 10 people will be added to this total number in case of bad quality data, outliers, etc. For instance, with this definition, if our estimate is at 50%, we will be 95% sure that the real figure will be within this range [44.5%; 55.5%]. To sum up, we will visit 640 households in 32 villages which is 20 households per villages. These 2 maps show the union councils where the villages have been selected. Map 2: Swabi district with the selected UCs for the survey
Naranji Parmoli
T/c Nawe Kali
Ismaila
Turlandi 2
Yar Hussain West
Gabasni
Sheikh Jana Chack Nodeh
Kab Ghani
Turlandi 1
Yar Hussain East
Saleem Khan
Dagai Bachai
Dhobian Sard CheenaYaqoobi
Ganichitra
Shewa
Asota
Adena Kalo Khan
Pabeni
Maniri Bala
Jhanda
Swabi
Gandaf
Maniri Payan
Sodher
Mainai
Bam Khel Punj Pir Lahore Poree
Lahor Tehsil
Lahore Raporee
T/c Zaida
Thanda Kawai Marghuz
Kota
Anmbar
Topi East
Kala But Bata Kara
Jalbai Manki
Topi West
Swabi Tehsil KundaShah Mansoor
Jalsai
Gar Munara
Zarobi
Turdher Mathani Changan Beka Jehangira
Blue: Door to door survey
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