ERR:ARGUMENT means a function received the wrong number of arguments — you gave it too few values, too many, or separated them incorrectly. It shows up constantly in stats class because commands like normalcdf( and binompdf( expect their inputs in an exact order. Here's how to fix it fast.
First: use Goto to find the problem
When the error screen appears, you get two options: 1: Quit and 2: Goto. Choose 2: Goto — the calculator jumps your cursor straight to the command that caused the error, so you don't have to hunt for it.
What "wrong number of arguments" actually means
Every TI-84 function has a fixed signature: a specific list of inputs, in a specific order, separated by commas. If you type normalcdf(70, 80) when the calculator needs a mean and standard deviation too, or you drop a comma so two numbers run together, you get ERR:ARGUMENT.
Two things trigger it most often:
- A missed comma —
normalcdf(70 80, 100, 15)merges two arguments into one - An extra trailing comma —
binompdf(10, .5, 3,)counts as an extra empty argument
Commas must separate every argument, with nothing left over at the end.
Correct signatures for the usual suspects
These are the functions that cause ERR:ARGUMENT most often, with the exact argument order the TI-84 expects:
| Function | Correct signature | What each argument is |
|---|---|---|
normalcdf( | normalcdf(lower, upper, μ, σ) | lower bound, upper bound, mean, standard deviation |
invNorm( | invNorm(area, μ, σ) | area to the left, mean, standard deviation |
binompdf( | binompdf(n, p, x) | number of trials, probability of success, number of successes |
binomcdf( | binomcdf(n, p, x) | trials, probability, successes (cumulative: 0 through x) |
round( | round(value, #decimals) | the number, how many decimal places |
seq( | seq(expr, variable, start, end, step) | expression, variable, start value, end value, step size |
Compare what's on your screen (after pressing 2: Goto) against this table. Count the commas. Nine times out of ten, one is missing or one is extra.
For a full walkthrough of the two stats commands that cause the most pain — including which bound goes where and what to type for "greater than" problems — see /guides/normalcdf-invnorm/.
The permanent fix: turn on Stat Wizards
If you're on a TI-84 Plus CE (OS 5.x), you can make this error nearly impossible to trigger for stats functions:
- Press
MODE. - Scroll down to STAT WIZARDS.
- Highlight ON and press
ENTER.
With Stat Wizards on, commands like normalcdf( and binompdf( open a fill-in-the-blank screen that prompts you for each argument by name — lower, upper, μ, σ — instead of making you memorize the order and type raw commas. You literally cannot pass the wrong number of arguments this way.
If you're taking the SAT or an AP exam, turn this on now and leave it on. It costs nothing and removes an entire category of mistakes under time pressure.
Quick checklist
- Press
2: Gototo jump to the broken command - Count the arguments against the table above
- Check every comma — no missing ones, no trailing one
- On a TI-84 Plus CE, set
MODE→ STAT WIZARDS: ON
Still seeing a different error message after fixing the arguments? Identify it in the full list at /error-fixes/error-messages/.
Try it right now
Practice the fix on the free online TI-84 calculator — a TI-84 Plus CE emulator that runs right in your browser with no download. Type a normalcdf( with a missing comma, trigger the error, then turn on Stat Wizards and feel the difference before test day.