find the missing probability in the table below :
x) P(X) 1) 0.30 2) 0.40 3) 0.15 4) ?

Question

find the missing probability in the table below :
x) P(X) 1) 0.30 2) 0.40 3) 0.15 4) ?

aum · Answer

There must be more information to this question.  Something is missing.

anonymous · Answer

NO ITS JUST THIS @aum

here_to_help15 · Answer

Let me try:)

aum · Answer

Can you post a screenshot of the question?

anonymous · Answer

OK HOLD ON @aum

anonymous · Answer

attachment

anonymous · Answer

@aum

aum · Answer

There must be something above, maybe a diagram or some other earlier data to which this question applies.

anonymous · Answer

no there is nothing more than this @aum

aum · Answer

What was the question previous to this?

anonymous · Answer

just to find the probability of the chart ! @aum

aum · Answer

So they are referring to some chart.  If you keep going back somewhere you may find something that says to the effect: for the following questions use this chart or diagram or data.

anonymous · Answer

This was the only chart there @aum

aum · Answer

I think there is missing info and I am not able to answer with what is provided.

anonymous · Answer

its ok @aum thanks anyway

here_to_help15 · Answer

I'll try lemme see.:)

here_to_help15 · Answer

All probabilities in a probability distribution must add to 1


So let x = missing probability


This then means that


0.3 + 0.4 + 0.15 + x = 1


0.85 + x = 1


x = 1 - 0.85


x = 0.15


So the missing probability is 0.15


Now we're tasked to find P(X > 2)


P(X > 2) = P(X = 3) + P(X = 4)


P(X > 2) = 0.15 + 0.15

here_to_help15 · Answer

P(X > 2) = 0.3

here_to_help15 · Answer

hope that helped a lil:)

anonymous · Answer

yes it did but what was the answer @Here_to_Help15

here_to_help15 · Answer

P(X>2)=0.3

anonymous · Answer

thanks @Here_to_Help15

here_to_help15 · Answer

your welcome :)

aum · Answer

Shouldn't there be a statement somewhere that states the following table represents a COMPLETE probability distribution?

here_to_help15 · Answer

That is true @aum but all i did was pull what ever i could from this question.

aum · Answer

You did a good job!

here_to_help15 · Answer

Thank you:)

anonymous · Answer

thanks to both @aum @Here_to_Help15

aum · Answer

The problem should have stated somewhere that X can have only 4 values: 1, 2, 3 and 4.  That would make it a COMPLETE probability distribution and we can conclude the probabilities will all add up to 1.