Explain what is meant by the variance of a set of obervations and then define the standard deviation of a set of obervations.

Explain what is meant by the variance of a set of obervations and then define the standard deviation of a set of obervations.

Part of my math project help needed! Extra info: “Many standard statistical methods are intended for use with distributions that are symmetric and have no outliers. These methods start with the mean and the standard deviation.”