Availability & Reliability

good day

im new on the Availability & Reliability study.

i am asigned to do Availability & Reliability for specific machine

they give me these data

1- total hours in month (720 hours in month)

2- schaduled Shutdown(preventive mentatice or somtime there are projects or upgrade)( 100 hrs as example)

3- UnSchduled Shutdowns (Breakdowns)( 120 hrs as example)

4- Standby ( avialable but not needed maybe)(50 hr as example )

5- running hours= 450 hrs as example

the aviability1 =(Total hours - unschduled Shutdown ) / total hours

or

aviability2=(Total hours - unschduled Shutdown -Schaduled Shutdown) / total hours

1 -which one is correct aviability1 or avaiablity2 formula and why? should we add the schduled hours on the avaiblity formula? or no

2- what is the formula for the reliabilty of this unit? is it same as avaibilty? or what