Statdisk Online is the leading free full featured statistical analysis package. It includes over 70 functions and tests, built-in Appendix B datasets, and graphing.

How do I download Statdisk?

Statdisk is a free download at They have both an online “web app” and a PC download. Select your operating system, either Microsoft Windows or Apple OSX.

What Statdisk 13?

Statdisk 13 includes all datasets for the new Elementary Statistics 13th Edition. New features include the ability to directly use lists of data instead of requiring summary data.

How do you find the critical value?

In statistics, critical value is the measurement statisticians use to calculate the margin of error within a set of data and is expressed as: Critical probability (p*) = 1 – (Alpha / 2), where Alpha is equal to 1 – (the confidence level / 100).

What is the symbol for standard deviation?

The symbol of the standard deviation of a random variable is “σ“, the symbol for a sample is “s”. The standard deviation is always represented by the same unit of measurement as the variable in question.