# S2 - can you explain something to me...

WatchPage 1 of 1

Go to first unread

Skip to page:

This discussion is closed.

P(X≥4)=1-P(X≤3)

i cant understand this,

P(X≥4)=1-P(X≤4) makes more sense to me

cos if we draw the graph, where area under the graph = probability=1, and mark the region X≥4, i dont see how its possible to get X≥4 by 1-(X≤3)

i cant understand this,

P(X≥4)=1-P(X≤4) makes more sense to me

cos if we draw the graph, where area under the graph = probability=1, and mark the region X≥4, i dont see how its possible to get X≥4 by 1-(X≤3)

0

Report

#2

Basically its cos binomial distribution is discrete not continuous so you have to use consecutive integers.....i think

can anyone else confirm?

can anyone else confirm?

0

Report

#3

P(X≥3) = P(X=3) + P(X=4) + P(X=5) etc

P(X≤3) = P(X=0) + P(X=1) + P(X=2) + P(X=3)

They would both include X=3, so it's P(X≤2).

Although I find it easier to look at as P(X≥3) = 1 - P(X<3)

and P(X<3) = P(X≤2) for discrete distributions.

Dunno why and maybe it's just me prefers to think of it like that

P(X≤3) = P(X=0) + P(X=1) + P(X=2) + P(X=3)

They would both include X=3, so it's P(X≤2).

Although I find it easier to look at as P(X≥3) = 1 - P(X<3)

and P(X<3) = P(X≤2) for discrete distributions.

Dunno why and maybe it's just me prefers to think of it like that

0

Report

#4

(Original post by

Basically its cos binomial distribution is discrete not continuous so you have to use consecutive integers.....i think

can anyone else confirm?

**Adil Bhai**)Basically its cos binomial distribution is discrete not continuous so you have to use consecutive integers.....i think

can anyone else confirm?

0

Report

#5

P(X >= 4) = 1 - P(X < 4) is always true, because exactly one of the events {X >= 4} and {X < 4} must occur.

If X is integer-valued then P(X < 4) = P(X <=3) so P(X >= 4) = 1 - P(X <= 3).

If X is integer-valued then P(X < 4) = P(X <=3) so P(X >= 4) = 1 - P(X <= 3).

0

Report

#6

(Original post by

P(X≥4)=1-P(X≤3)

i cant understand this,

P(X≥4)=1-P(X≤4) makes more sense to me

cos if we draw the graph, where area under the graph = probability=1, and mark the region X≥4, i dont see how its possible to get X≥4 by 1-(X≤3)

**RussianDude**)P(X≥4)=1-P(X≤3)

i cant understand this,

P(X≥4)=1-P(X≤4) makes more sense to me

cos if we draw the graph, where area under the graph = probability=1, and mark the region X≥4, i dont see how its possible to get X≥4 by 1-(X≤3)

Ok, think about it this way. below there are 10 dots, labelled 1 to 10, they represent a probability distribution, so their sum is 1.

1 2 3 4 5 6 7 8 9 10

o o o o o o o o o o

1 2 3 4 5 6 7 8 9 10

o o o o o o o o o o

P(X≥5) are the numbers 5 to 10, right? This is also the same as 1 (i.e. everything) - P(X≤4)

So, in essence P(X≥x) = 1 - P(X≤x-1)

0

X

Page 1 of 1

Go to first unread

Skip to page:

new posts

Back

to top

to top