Question

Assume that when adults with smartphones are randomly​ selected, 57​% use them in meetings or classes. If 77 adult smartphone users are randomly​ selected, find the probability that at least 3 of them use their smartphones in meetings or classes.

Is it possible to use the TI-83/84 to solve this problem.

Thank you

Answer 1

p = 0.57

n = 77

We have to find the probability that at least 3 of them use their smartphones in meetings or classes.

That is we have to find P(X 3)

Here X follows Binomial distribution.

By using the TI-84 calculator we have to find the probability.

P(X 3) = 1 - P( X 2)

TI-84 calculator path is Click on 2ND --------> VARS ---------> binomcdf( ------------>

trials: 77

p: 0.57

x value: 2

Click on Paste.

We get

P( X 2) = 0.0000

P(X 3) = 1 - P( X 2) = 1 - 0.0000 = 1

The probability that at least 3 of them use their smartphones in meetings or classes is 1.