I am going to conduct a research to assess childbirth fear among last trimester pregnant women and 6 weeks postnatal mothers
There are two approaches of selecting a sample Size. If you know the population i.e. the number of pregnant women (whoever are targeted), You can apply "probability based sampling" method. The formula is available on google and can be searched simply by name "probability based sampling size calculator".
The second is non-probability based sampling approach if you don't know about the pregnant women. This formula also available on net. As a rule of Thumb, the non-probability based sampling formula applies when you have more than 50,000 population size.
Best,
Thank you Dear Anwar for your response,
I have other questions which a reviewers usually raise the questions in clinical research.
Suppose,
1. I do a clinical research; let’s say clinical outcomes of a surgical procedure. I have total number of operated patients are 50 in a particular time (let’s say -2014-2016) and I want to measure the postoperative outcome of that patients. How can I calculate a required sample size?
2. In a comparative study, I want to compare the postoperative outcome of a surgical procedure in two different groups of patients (Let’s say between 2014-2016) and Group A has total cases 50 and B also has 50. Now I want to compare the clinical outcomes of improvement of 2 groups of patients. How can I calculate a required sample size?
Since you have only 50, 50 respondents, why not the finite population to that should be 100 as a whole. Otherwise, apply probability based formula bcs in your case, you know about ur total number of respondents.
Sample size =Z2 x P x (1-P)/C2
Where, Z= Z value
P= incidence of given outcome from previous study
C= confidence interval
value of Z and C depends upon confidence level and confidence level, you take for your study.
Nira Tamang could you find how calculate the sample size? if you can plz help me as well@Nira Tamang
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