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How to find a binomial probability on a TI-83 Plus

By E-Code · updated

Press 2nd CATALOG (above 0), APPS to jump to B, ▼ to binompdf( and ENTER. Type trials, p and x with commas, close the bracket and press ENTER: binompdf(10,.5,5) is .2461.

Step by step

  1. Open CATALOG. 2nd 0 Press 2nd, then 0. CATALOG lists every command A to Z.
  2. Jump to B. APPS Letters are on, so press APPS (the B key): the list jumps to the commands starting with B.
  3. Down to binompdf(. ▼ ▼ Press ▼ until the arrow points at binompdf( (pdf: exactly x; cdf: x or fewer).
  4. Paste it. ENTER Press ENTER. binompdf( is pasted on the home screen.
  5. Trials, p and x. 1 0 , . 5 , 5 ) Type 10 , .5 , 5 ): 10 flips, a 0.5 chance of heads each, exactly 5 heads.
  6. Work it out. ENTER Press ENTER.
  7. Read the chance. .246: exactly 5 heads in 10 flips happens about 25% of the time. binomcdf(, just above it, gives 5 or fewer.

What the screen shows

.246: exactly 5 heads in 10 flips happens about 25% of the time. binomcdf(, just above it, 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

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