Probability distribution question

[princejan7]

Homework Statement

http://postimg.org/image/bleosmrep/

Homework Equations

The Attempt at a Solution

can someone explain the last line of the solution; where did 1 - 6.25/10^2 come from?

 

[Ray Vickson]

Homework Statement

http://postimg.org/image/bleosmrep/

Homework Equations

The Attempt at a Solution

can someone explain the last line of the solution; where did 1 - 6.25/10^2 come from?

You are supposed to show your work (PF rules). So, first you need to tell us what you think the method is.

 

[princejan7]

You are supposed to show your work (PF rules). So, first you need to tell us what you think the method is.

I'm not really sure what they're doing at all
I want to know why they reduced the original problem to P((X-u)<10)

 

[jbunniii]

I'm not really sure what they're doing at all
I want to know why they reduced the original problem to P((X-u)<10)

They're applying a standard inequality. What inequalities do you know which involve the mean and variance?