You can use the Formula Auditng which includes the Evaluate facility and Trace Precedents, which would be useful.
Function
function
the asterisk is used for what function when building a formula in excel
You can use the Insert Function button fx on the Formula bar to find an Excel function by typing a description of the formula at the Insert Function dialog box, in the Search for a function text box and then click Go.
You are probably referring to the formula bar. It displays the current content of cells and allows you to add in formulas, labels or values into a cell. You can also start the Insert Function dialog box by clicking on the fx at the beginning of the formula bar. You can choose a function from there and it can be included in a formula.
an equal sign =
Excel has a ZTEST function. It has the format ZTEST(array, µ0, sigma).
To tell Excel that you are typing a formula, start by typing an equal sign "=" in the cell where you want the formula. This signals to Excel that you are entering a calculation or function. You can then proceed to input the formula or function you want to use in that cell.
Insert Function in Excel allows you to enter a function into your worksheet. You can choose your function from different categories fo functions. It will also give you a little help on the function so that you can use it in the correct way.
A nested formula is where one or more functions are placed inside another function to make a formula. For example you can write a formula where you put an IF function within an IF function and this would be a nested formula.
prefix the excel function with application. eg. a=application.evaluate("1+2+3")
The SUM function would be the most commonly used function in Excel.