Texas Instruments TI-83 PLUS - Manual (Page 340)

TI-83 Plus Statistics 337
4. Press ƒ [ ã ], enter the formula, and press ƒ [ ã ].
Note: If you do not use quotation marks, the TI-83 Plus calculates and
displays the same initial list of answers, but does not attach the formula for
future calculations.
Note: Any user-created list name referenced in a formula must be preceded
by an
Ù symbol (Chapter 11).
5. Press Í . The TI-83 Plus calculates each list element and stores it
to the list name to which the formula is attached. A lock symbol is
displayed in the stat list editor, next to the list name to which the
formula is attached.
lock symbol