Nigeria - National Agricultural Sample Census Pilot (Private Farmer) Fishery-2007, Fourth round

12 states were purposely selected in the country.
2 states from each of the 6 geo-political zones.
2 LGAs per selected state were studied.
2 Rural EAs per LGA were covered and
3 Fishing farming Housing Units were systematically selected and canvassed .
However, more fishing farming housing units were over sampled in the six (6) reported States


There was deviations from the original sample design


Both Enumeration Area (EA) and Fish holders' level Response Rate was 100 per cent.



The formula adopted in calculating the design weights for the survey data (sample results) were as follows:

(i) The probability of selecting an EA within a state was obtained by dividing the total number of EAs sampled in a
state by total number of EAs in that particular state. Let this be represented by fj. That is,
fj = (Total Number of EAs sampled in a state)/(Total Number of EAs in that particular State)

(ii) Likewise, the probability of selecting an housing unit (HU) within an EA was obtained by dividing the total number
of housing units selected in an EA by the total number of housing units (HUs) listed in that particular EA. Let this be
represented by fk. That is,
fk = (Total Number of HUs selected in an EA)/(Total Number of HUs listed in that particular EA)

Then the product (fj) x (fk) represented by f is the sampling fraction for each of the corresponding study unit (Enumeration Area) for all the 48EAs canvassed throughout the 12 states of the Federation. The inverse of the sampling fraction is known as the design weight and was applied accordingly to all the study units.

Mathematically,
Design weight = ((Total number of EAs in a state)/(Total number of EAs sampled in that particular state)) X ((Total Number of HUs listed in an EA)/(Total Number of HUs selected in that particular EA))

The above value was obtained for each of the 48EAs canvassed throughout the 36 states of the Federation. Thereafter, adjustment factors were applied to adjust for the non-responses.