Question 877978
<pre>
Yes, that's a binomial problem.  The probability that there are 19 or
fewer successes out of 20 trials, where the probability of success in ONE
trial is .99

n = 20 trials
p = .01 = probability of 1 "success" in 1 trial.

Note: Here a "success" is that a person would be satisfied.

x <= 19

With my TI-84

Press ON
Press CLEAR
Press 2ND
Press VARS
Use down arrow key to scroll to B:binomcdf(
Press ENTER

Depending on how old your calculator is or what mode it is in,
you may see this:

                         binomcdf
                      trials:
                      p:
                      x value
                      Paste

If so make it read      binomcdf
                      trials:20
                      p:.99
                      x value:19
                      Paste

Highlight Paste
Press ENTER

You'll see:  

binomcdf(20,.99,
19)

Or if you have an old TI-84 see binomcdf(
Make it read 

binomcdf(20,.99,
19)

Press ENTER   

You'll see .0010035762

Edwin</pre>