How Do You Calculate A Confidence Interval?
When analyzing the sample data from an experiment or research study, perhaps one of the most important statistical parameters is the mean: the numerical average of all the data points. However, statistical analysis is ultimately a theoretical model imposed on a set of concrete, physical data. To account for the inherent imprecision of statistical modeling, use confidence intervals to evaluate the reliability of the mean (and other parameters). A confidence interval is a range of values within which a parameter is likely to be found. The larger the interval, the higher the probability of it including the actual parameter. Add together the value of every data point in the sample. Divide this sum by the total number of data points. This is the mean value for the sample. Subtract the mean from the lowest value of all the data points. For example, in the set of five data points with values of 3, 6, 11, 2 and 4, the mean would be 5.2, or (3+6+11+2+4)/5 = (26)/5 = 5.2. Since “2” is the lowest
