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; Symbol Property Mean of the sample Standard score 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… Continue reading Calculating Probabilities Using The Confidence Interval Formula