## MathSofiya 3 years ago @CliffSedge I have a table here that I don't quite understand x 0 1 2 3 4 5 P(x) 0.237 0.396 0.264 0.088 0.015 0.001 x= # of prisons out of 5 on parole who become repeat offenders. What is P(x)? and why does it add up to 1?

1. CliffSedge

If they add up to 1, those could be probabilities or proportions.

2. MathSofiya

Criminal Justice: Parole USA Today reported that approximately 25% of all state prison inmates released on parole become repeat offenders while on parole. Suppose the parole board is examining five prisoners up for parole. Let x= number of prisoners out of five on parole who become repeat offenders. The methods of Section 5.2 can be used to compute the probability assignments for the x distribution.

3. MathSofiya

so x from 0 to 5 are not "the prisoners"

4. MathSofiya

I guess I don't understand what x is...sigh

5. CliffSedge

It is a little strangely worded, but it says that x is number out of 5, so x itself is a proportion.

6. CliffSedge

e.g. x=3 means 3 out of the 5 prisoners up for parole will be repeat offenders.

7. MathSofiya

$\frac05$ why is there are chance for repeat offense?

8. MathSofiya

probability I mean

9. CliffSedge

*shrug* that's just what they are measuring here.

10. MathSofiya

so when no one is on parole the probability or re-offending is 0.237? That's what they're trying to tell me?

11. MathSofiya

*of

12. CliffSedge

No, it's saying that for every 5 prisoners out on parole the probability that 0 of them will offend again is 0.237

13. MathSofiya

OOHHHHHH....LOL! That makes much more sense! haha

14. MathSofiya

5 are out on parole at all time I guess

15. CliffSedge

It's just an average 'per 5' basis. There could be 100 parolees, so x=3 means 60 out of 100.

16. MathSofiya

one last thing...

17. MathSofiya

the probability that 5/5 parolees will re-offend is very slim? highly unlikely?

18. CliffSedge

Yeah, 0.001 is pretty low, 1-in-1,000 chance, but if there are 5,000 parolees, then that's practically a sure thing.

19. CliffSedge

(Practically a sure thing to get 5 out of 5,000, not 5,000 out of 5,000 that is)

20. MathSofiya

Yep makes sense. Thank you once again!

21. CliffSedge

My pleasure.