3.2.3 Sampling techniques and sample
size
Simple random sampling was employed in order to secure
necessary data from the study area, which gave a chance to every individual
household in the study area. To determine the sample size, the following
formula was used (Javeau, 1985):
n= Nxno
N+no
Where n is the sample size,
N is the population size within the study area.
no is the constant
N: B In the study area, the target population was represented
by households and the total number of households in Amahoro cell was 1576, no
(the constant) is calculated from two complementary events p and q. where
p=q=0.5 p+q=1
In his theory, Cochran (1963:75) developed the equation which
gives the value of no as follows:
no= z^{2}xpxq
e^{2}
Where z is the threshold of confidence which is estimated to
be equal to 2 and e is the stroke of errors that is estimated to 10% or
0.10.
Then,
no= 2^{2}x0.5x0.5
0.10^{2}
Therefore, n=Nxno n= 1576x100
N+no 1576+100
n= 94
However, the sample size that was surveyed in the study area
was 100 households.
The respondents were selected (at random) in equal proportions
in the whole villages comprising Amahoro cell (table 2). To get the sample size
for Umudugudu, we took the total number of the households in the cell and
divided it by the number of the households in the Umudugudu, multiplied by 100.
i.e. Sample size in Umudugudu= Households in Umudugudu
x100
Households in a cell
Table 2: Surveyed households in each
Umudugudu
Umudugudu

No. of households

Population

Sample size

Amahoro

130

843

9

Amizero

415

914

26

Inyarurembo

126

555

8

Kabirizi

256

847

16

Ubuzima

395

989

25

Uruhimbi

254

935

16

Total

1576

5,083

100

Source: executive secretary/Amahoro
cell
Also leaders and decision makers at different levels in Kigali
city were interviewed. The following table shows the categories of interviewed
leaders:
Table 3: Interviewed local leaders in Kigali
city
Administrative level

Position held

Cell

Executive secretary

Sector

Personnel in charge of social affairs

District

Land and infrastructure manager

Rwanda housing authority (RHA)

Personnel in charge of planning

Source: Author, 2011
