What is the purpose of the Excel Function Reference?
to look up functions and their purposes
to add customized functions to the list
to delete functions from the list
to sort and organize functions in the list

To insert a column without using commands in any tabs, a user can -click and then click insert column.

Least square fit to polynomial write a function leastsquarefit3pol that solves a linear system of equations to find a least squares fit of a third order polynomial to an experimental data set given as two row arrays. the function leastsquarefit3pol must explicitly solve a set of linear equations and cannot use polyfit. there should be no restriction on the size of the problem that can be solved.

Which statistical function in a spreadsheet you to see how far each number varies, on average, from the average value of the list?