# s1 question

Watch
Announcements
Thread starter 5 years ago
#1
Three independent values of X are chose, X1, X2, X3, it is given that X1+X2+X3 = 19, find sets of values for X1, X2 and X3 and find the probability P(X=7)

x 1 3 5 7
P(x=x) 0.4 0.3 0.2 0.1

I have the set of values as 775, 757, 577, now what do I do? :/
0
5 years ago
#2
(Original post by jacksonmeg)
Three independent values of X are chose, X1, X2, X3, it is given that X1+X2+X3 = 19, find sets of values for X1, X2 and X3 and find the probability P(X=7)

x 1 3 5 7
P(x=x) 0.4 0.3 0.2 0.1

I have the set of values as 775, 757, 577, now what do I do? :/
Do you have a link to the original question, or its exact wording. To find the probability X=7, doesn't make sense. P(X1=7) given the previous, for instance, would be a reasonable question to ask.
0
Thread starter 5 years ago
#3
(Original post by ghostwalker)
Do you have a link to the original question, or its exact wording. To find the probability X=7, doesn't make sense. P(X1=7) given the previous, for instance, would be a reasonable question to ask.
its june 2013 and I can't link it, i'll type it out exactly

Three independent values of X, denoted by X1, X2, X3 are chosen
Given X1 + X2 + X3 = 19, write down al possible sets of values for X1, X2, X3 and hence find P(X1=7)
0
5 years ago
#4
(Original post by jacksonmeg)
its june 2013 and I can't link it, i'll type it out exactly

Three independent values of X, denoted by X1, X2, X3 are chosen
Given X1 + X2 + X3 = 19, write down al possible sets of values for X1, X2, X3 and hence find P(X1=7)
OK. All three of those possibilities (775, 757, 577) are equally likely. Two of them have X1=7, hence the probability X1=7, given those three, is....
0
5 years ago
#5
(Original post by ghostwalker)
OK. All three of those possibilities (775, 757, 577) are equally likely. Two of them have X1=7, hence the probability X1=7, given those three, is....
Sorry for hijacking the thread. Is it just 2/3?

Posted from TSR Mobile
0
5 years ago
#6
(Original post by Lamalam)
Sorry for hijacking the thread. Is it just 2/3?

Posted from TSR Mobile
Spoiler:
Show

Yep.
0
X

new posts
Back
to top
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### Poll

Join the discussion

#### What factors affect your mental health the most right now? (select all that apply)

Lack of purpose or routine (120)
15.58%
Uncertainty around my education (125)
16.23%
Uncertainty around my future career prospects (72)
9.35%
Isolating with family (51)
6.62%
Lack of support system (eg. Teachers, counsellors) (30)
3.9%
Lack of exercise/ability to be outside (66)
8.57%
Loneliness (81)
10.52%
Financial worries (32)
4.16%
Concern about myself or my loved ones getting ill (70)
9.09%
Exposure to negative news/social media (50)
6.49%
Lack of real life entertainment (eg. cinema, gigs, restaurants) (73)
9.48%