How to find a binomial probability on a TI-84 Plus CE or TI-84 Plus

By E-Code · updated 2026-09-27

Press 2nd DISTR (above VARS), then ALPHA MATH for A: binompdf(. In the wizard type trials, p and x value, pressing ENTER after each, then ENTER on Paste and ENTER again: binompdf(10,.5,5) is .2461.

Step by step

1. Open DISTR. 2nd VARS Press 2nd, then VARS (DISTR).
2. Pick binompdf(. ALPHA MATH Press ALPHA, then MATH: A picks item A, binompdf(, further down the list. A wizard opens.
3. Trials: 10. 1 0 ENTER Type 10 and ENTER: 10 flips.
4. Chance p: 0.5. . 5 ENTER Type .5 and ENTER: the chance of heads on each flip.
5. X value: 5. 5 ENTER Type 5 and ENTER: exactly 5 heads.
6. Paste. ENTER The cursor is on Paste. Press ENTER: the command goes to the home screen.
7. Work it out. ENTER Press ENTER.
8. Read the chance. .246: exactly 5 heads in 10 flips happens about 25% of the time. binomcdf(, item B, gives 5 or fewer.

What the screen shows

.246: exactly 5 heads in 10 flips happens about 25% of the time. binomcdf(, item B, gives 5 or fewer.

Look for .24609375 on the screen.

Try it with the keys lit up

This guide is one of E-Code's Learn lessons. Open it on E-Code's TI-84 calculator and each key lights up in turn as you press it.

Try “Find a binomial probability” on the TI-84 calculator

Related

• Find mean and standard deviation
• Find mean and standard deviation (TI-83 Plus)
• Show r and r² on a regression (TI-84 Plus CE)
• Show r and r² on a regression (TI-84 Plus)
• Show r and r² on a regression (TI-83 Plus)

Statistics programs for the TI-84 Plus CE:

• Regression: linear, quadratic, exponential with r²
• Hypothesis tests: z, t, two-sample t, chi-square
• Confidence intervals: z, t, proportion, two-sample

All TI-84 statistics guides · All TI-84 guides · All calculator guides