Microsoft Word research method fm doc

 
Solution 
The required sample to show, with a 90% likelihood (power), that the percentage of nurses is 
different in these two regions would be:
(assume a confidence level of 95%) 
n = (1.28+1.96)
2
((.3
×.7) +(.15 ×.85)) / (.30 - .15)
2
= 158 
158
nurses are required in each region 
 
Comparison of two means (sample size in each group
) 
n = (s
1
2
 + s
2
2
) f(
α,β) / (m
1 
- 
 
m
2
)
2 
m
1
and s
1
2
are mean and variance of group 1 respectively. 
m
2
and s
2
2
are mean and variance of group 2 respectively. 
 
 
N.B. Sample size calculation using the STATCALC calculator of the Epi Info program is 
given in chapter 8. 
 
 

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Research methodology 
51
6.8 Plan for data collection 
 
Why should you develop a plan for data collection? 
A plan for data collection should be developed so that: 
• 
you will have a clear overview of what tasks have to be carried out, who should 
perform them, and the duration of these tasks;
• 
you can organise both human and material resources for data collection in the most 
efficient way; and
• 
you can minimise errors and delays which may result from lack of planning (for 
example, the population not being available or data forms being misplaced).
It is likely that while developing a plan for data collection you will identify problems (such as 
limited manpower), which will require modification of the proposal. Such modifications might 
include adjustment of the sample size or extension of the period for data collection.