Data analysts are often faced with the problem of what their sample size should be. Some sample sizes are so small that it becomes difficult to draw conclusions from the research. On the other hand, other surveys are so large that it becomes too expensive to collect and analyze the data. There are mathematical formulas that the analyst can use to decide on his sample size. The formulas will also give him his margin of error. He has to look into how many people will respond to his survey and how many will not. These factors help him decide the sample size.