Technology Tips for Probability

Technology Tips for Probability

EXCEL:

Permutations: nPr Type into Excel anywhere on the spreadsheet:

= PERMUT (n,r) to select r objects out of n objects and order matters. For example, to find Permutations 10 things 3 at a time, you would type =PERMUT(10,3) then hit ENTER

Combinations: nC r to select r objects out of n objects and order does not matter. Type anywhere on the spreadsheet:

=COMBIN(n,r) For example, to fine Combination 10 things taken 3 at a time, you would type:

=COMBIN(10,3) anywhere on the spreadsheet then hit ENTER

Factorials:

For example to find 3! Type anywhere in the spreadsheet: =FACT(3)

To Find Binomial Probabilities:

type anywhere in the spreadsheet: =BINOMDIST(x,n,p,0)

to find the probability of EXACTLY x successes in n trials with a probability of p. For example, to find the probability of 0 successes in 7 trials with a probability of success of .25, type

=BINOMDIST(0,7,.25,0) and you will get .1335 when rounded.

To find the probability of less than 3 successes, for example, type:

= BINOMDIST(2,7,.25,1) and you will get approx .7565.

To find the probability of more than 3 successes, for example, type:

= 1- BINOMDIST(3,7,.25,1) and you will get approx .0706

TI 83/84 Instructions

Combinations (10,3) for example:

Type in 10, go to MATH, scroll over to PRB, enter