Uh oh! Wolfram|Alpha doesn't run without JavaScript.
Please enable JavaScript. If you don't know how, you can find instructions
here
.
Once you've done that, refresh this page to start using Wolfram|Alpha.
P(X<(3.5-4.2)/0.9)
P(X<(3.5-4.2)/0.9)
Natural Language
Math Input
Extended Keyboard