How would I work these out?

[Ghost21432]

 

[mmm4444bot]

Posting Guidelines (Summary)

Welcome to our tutoring boards! :) This page summarizes main points from our posting guidelines. As our name implies, we provide math help (primarily to students with homework). We do not generally post immediate answers or step-by-step solutions. We don't do your homework. We prefer to help...

www.freemathhelp.com

 

[Agent Smith]

k is the factor by which we have to reduce the standard deviation, but I don't know what I should do next.