# Variable meaning

I want help understanding the following statement. I need to be able to use this formula but I don't quite get it. What does the little n stand for? So suppose my universe is 15 usability problems and each subject gets 20% of them (the L) how do you use the little N in this equation to get the result? Here is the paragraph that I want to understand:

"Tom Landauer and I showed that the number of usability problems found in a usability test with n users is:

N(1-(1-L)n)

where N is the total number of usability problems in the design and L is the proportion of usability problems discovered while testing a single user. The typical value of L is 31%, averaged across a large number of projects we studied."

Â© BrainMass Inc. brainmass.com March 4, 2021, 5:52 pm ad1c9bdddfhttps://brainmass.com/math/algebra/variable-meaning-interpreting-15076

#### Solution Preview

little n stands for number of users.

In your case, if it's ...

#### Solution Summary

This gives one example of interpreting a variable in an equation.