Use of TI-83 Calculator to Compute
Poisson Probability Distribution Values

Example (TI-83): Find the probability that 3 successes will occur if the average number of successes is 3/4. That is, find P(x = 3).

 

Press 2nd VARS [DISTR].

Scroll down to

C:poissonpdf(

Press ENTER.

Enter 3/4,3)

and press ENTER

to get the answer .03321.

The syntax is poissonpdf(mean, x-value).

Example (TI-83): Find the probability that 3 or less successes will occur if the average number of successes is 3/4. That is, find P(x ≤ 3).

 

Press 2nd VARS [DISTR].

Scroll down to

D:poissoncdf(

Press ENTER.

Enter 3/4,3)

and press ENTER

to get the answer .9927.

The syntax is poissioncdf(mean, largest x-value).

Example (TI-83): Find the probability that at least 3 successes will occur if the average number of successes is 3/4. That is, find P(x ≥ 3). Use the complement rule to find P(x ≥ 3) = 1 P(x ≤ 2).

 

Press 1 and 2nd VARS [DISTR].

Scroll down to

D:poissoncdf(

Press ENTER.

Enter 3/4,2)

and press ENTER

to get the answer .0405.

The syntax is 1 poissoncdf(mean, largest x-value).