The mean symbol, or "x-bar,” is a descriptor that indicates sample average in mathematic equations, most often in statistics. Microsoft Word includes the ability to add this symbol using the Equation Tools Design tab. By accessing this tab, you can easily add an accent to the an "x" to create a professional-looking mean symbol. Once you've created the symbol, it's far easier to add it to your AutoCorrect options than re-create it each time you need it for an equation.
Open Microsoft Word, and then open the document in which you need to insert the symbol.
Place your cursor where you need the symbol inserted.
Navigate to the Insert tab, and then click "Equation."
Click the "Accent" down arrow from Equation Design, and then select "Bar."
Click beneath the bar symbol, and then type an "x."
To insert the x-bar as a symbol that AutoCorrect uses, highlight the symbol. From the File tab, select "Options."
From the list of Proofing options, select the button "AutoCorrect Options." On the AutoCorrect tab, type the text to automatically be replaced by the x-bar symbol in the "Replace" field. Click "Add," and then "OK."
Always save a copy of the mean symbol as a picture or graphics file in Window \"Paint\" before attempting to use for websites as the symbol doesn't translate to web applications from Word---the overbar and (x) separate into two characters rather than one symbol. To save as a picture or graphic file, copy your mean symbol in Word. Click \"Start\" and under \"All Programs\" go to \"Accessories\" and then \"Paint\" from the menu. Paste the symbol and save as a JPEG file.