Question

Propose a survey relted to nursing practice. Include title, purpose, number of items, and how you calculated your sample size.

Answer 1

I would propose survey for cardiac health assessment. Out of all possible surveys we can do study on risk of cardio-vascular disease with obesity. We can examine arterial stiffness non-invasively for survey purpose. The title would be like this " The study of association between Arterial Stiifness and obesity Indices"

The purpose of this study would be to analyse risk of getting cardio-vascular disease due to obesity. It is well known fact that stiffer the arteries, more the chances of cardio-vascular disease (coronary arterial disase). Arteries become stiffer if have to bear high blood pressure. And stiffer arteries are less elastic. Thus if arteries are getting stiffer then coronary vessels (heart vessels) may get blocked or wud not expand in high demand of blood such as during exercise etc.. Non invasive machines are available who measure index of arterial stiffness by measuring puse Wave velocity (speed at which pulse generated in heart propagate). Arterial stiffness is directly propotional to the Pulse Wave Velocity(PWV)

According to above discussion we should measure the Pulse Wave velocities of different arteries such as artery from heart to brachial., Heart to ankle etc. Second we would measure weight and Height, waist Circumference (WC), Hip circumference to measure/calculate obesity indices. We would calculate Body Mas Index(BMI), Waist Hip ratio, Waist height ratio. Skin fold as indices of obesity. To rule out other most influencing factor like blood pressure we wud monitor blood pressure to wud exelude hypertensive participants from the study and Res

Then we can calculate the pearson's correlation coefficint to analyse the association between Pulse wave velocity (PWV) and BMI, PWV anc WC and so on. We can also perform multiple regression to find out most influencing factor on PWV.

Sample size calculation : here we would be trying to find the association between PWV and Obesity Indices(such as BMI) . We have to take as such sample that we could get correlation coefficient (r ) more than 0.3. as well as we wud set alfa( $\alpha$ ) error and power of the hypothesis statistical analysis and calculate beta ( $\beta$ ) error as $\beta = 1 - power$ . With the help of these 3 values we can calculate sample size using statistical software or appropriate formula.

As well as if we know the population of an area then we can calculate sample size according to population.

What sample size wud more we wud study on that more number of samples.