What:
How can you ever be sure that your data (and in turn calculations) are accurate in Statistics, like when calculating the Parameters of a Distribution? You can’t. So you introduce a Standard Error. That is is a number (a tool really) that lets you know how sure you can be about your result. The formula is:
Where:
- is the sample proportion
- is the sample size
Z Scores
Once you get the Standard Error, you can plug it into a normal distribution table (like the one in the Irish Formula and Tables booklet). That is then the confidence you have in your proportion’s success rate / whatever you’re trying to calculate.