Our advice
Confidence interval of a standard deviation and a mean

Even if the approach may seem tedious to those new to it, determining confidence intervals using the tools described in this data sheet is an essential part of understanding these phenomena. The use of spreadsheets and the functions (Student and Chi-square) integrated into them enable this to be done without any effort other than that of understanding their usefulness. Comparing two apparently different averages or two standard deviations, a frequent industrial problem, can only lead to relevant conclusions if this effort has been made.