Event independence little problem

In summary, the problem involves two events, A and B, where A represents the inequality y<=x and B represents the inequality y<=1-x. The question is whether these events are independent, and if B: x<=1/4, are they still independent? The attempt at finding a solution involves using the formula P(A|B) = P(A)P(B) / P(A)P(B)+(1-P(A))P(B) but the dependency of B on x makes it difficult to express mathematically. Graphing the inequalities can provide a visual representation of the independence of events A and B.
  • #1
atrus_ovis
101
0

Homework Statement


0<=x<=1 0<=,y <=1
event A: y<=x
event B: y<=1-x
Are events A,B independent?
Also, if B: x<=1/4 , are A,B independent?

The Attempt at a Solution


if independent,
P(A|B) = P(A)
P(A|B) = P(A)P(B) / P(A)P(B)+(1-P(A))P(B)
... ?

For B: x<=1/4 they are obviously dependent, as B normalizes the event space to the part
where x<=1/4, thus affecting the probability of A, since it involves x.
I can't express it mathematically though, in the formula.
 
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  • #2
atrus_ovis said:

Homework Statement


0<=x<=1 0<=,y <=1
event A: y<=x
event B: y<=1-x
Are events A,B independent?
Also, if B: x<=1/4 , are A,B independent?

The Attempt at a Solution


if independent,
P(A|B) = P(A)
P(A|B) = P(A)P(B) / P(A)P(B)+(1-P(A))P(B)
... ?

For B: x<=1/4 they are obviously dependent, as B normalizes the event space to the part
where x<=1/4, thus affecting the probability of A, since it involves x.
I can't express it mathematically though, in the formula.
Graph the inequalities y <= x and y <= 1 - x. Both of these are regions in the plane. The graphs should show you whether events A and B are independent.
 
  • #3
Hm,okay.Thank you.
And is this considered a legitimate answer?
Graphs, i mean.
 
  • #4
Well, the answer wouldn't be just a graph. You should say what it is that the graph represents as far as independence is concerned.
 
  • #5
Yes, yes of course.
Thank you for your help Mark :)
 

1. What is meant by "event independence little problem"?

The "event independence little problem" refers to a phenomenon in which the occurrence of one event does not affect the probability of another event happening. This is also known as the "independence of events" or the "independence assumption" in probability theory.

2. How is event independence determined?

Event independence is determined by analyzing the relationship between the events in question. If the probability of one event occurring remains the same regardless of whether or not the other event occurs, then the events are considered to be independent.

3. What are some examples of event independence?

Examples of event independence include flipping a coin and rolling a die. The outcome of one event (flipping a coin) does not affect the outcome of the other event (rolling a die). Another example is drawing two cards from a deck without replacement. The probability of drawing a certain card does not change based on whether or not another card was previously drawn.

4. How does event independence impact probability calculations?

Event independence is an important concept in probability calculations because it allows for simpler and more accurate calculations. When events are independent, the probability of the events both occurring is simply the product of the individual probabilities. For example, the probability of getting heads on a coin flip and rolling a 4 on a die is (1/2)*(1/6) = 1/12.

5. Can events be independent and dependent at the same time?

No, events cannot be both independent and dependent at the same time. Independence means that the occurrence of one event does not affect the probability of another event happening, while dependence means that the occurrence of one event does affect the probability of another event happening. However, events can be conditionally independent, meaning they are independent under certain conditions but not independent under others.

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