While conducting your research, determining your sample size is one of the early steps. You need to fix your sample size based on various logical analysis so that your research data is not compromised and it helps you get accurate results. While everyone would prefer a large sample size so that they can get maximum insights, it is an expensive affair to conduct research on large sample size. On the contrary, with a small sample size, you might not be able to get accurate results since you don’t know how effective the small group of the sample can be. The correct sample size can be determined by conducting a little background study.
Determine the population size: If you are doing research about the impact of digital media in the Youth of UK, your population is the total number of youth present in UK. You might not get an exact figure but an approximation will work just fine for your study.

The Margin of error: No amount of sample size can give you totally perfect results. You have to determine the margin of error that you are willing to accept in the study. Usually, the confidence interval is referred to as the margin of error and it can be + or – 5 %.

The confidence level: Your confidence level determines how you gauge the mean falls within the confidence interval. The widely used confidence levels are 90, 95 and 99%.
In order to determine the correct sample size, you need to understand the calculation of the Z score.
The equation for the same is,
Necessary Sample Size = (Z-score)² – StdDev*(1-StdDev) / (margin of error)²
Here, Z score can be calculated using a Z score table.
By using this equation, you can easily determine the right sample size for your research study!