Confidence Intervals can be used to estimate the population mean from a sample mean and finding a confidence interval can be calculated by using this formula;
|Mean of the sample|
|Standard deviation squared (variance)|
|Number in sample|
The Standard Score can be calculated by taking one away from the probability dividing by two and then adding the probability back to the answer and using the table to calculate. So for example, a probability of 95% would be,
Of which is found by using percentage points of the normal distribution.
Using a Confidence Interval of 95% would allow you to assume that you are 95% confident about your results and that there is supposedly a 5% area of doubt where the samples are uncertain, It is important to consider this factor when conducting a conclusive statement.