Statistics problem: rolling a die
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Statistics problem: rolling a die

[From: ] [author: ] [Date: 11-06-21] [Hit: ]
3, 4, 5,Numbers greater than 3 in a die are {4, 5,Odd numbers in a die are {1,......
If one die is rolled one time, find the probability of getting a number greater than 3 or an odd number. Please help it is for test review.

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N = total number of possible outcomes = {1, 2, 3, 4, 5, 6} = 6

Numbers greater than 3 in a die are {4, 5, 6}
Odd numbers in a die are {1, 3, 5}
n = total number of favorable outcomes = {4, 5, 6, 1, 3} = 5

Required probability P(A) = n/N = 5/6

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Having an OR in probability questions is always difficult. An AND function is much easier. If you know the chance of something A, and you know the chance of something B, the chance of A and B happening is the multiplication of the chance that A happens and the chance that B happens.

This isn't as easy for the chance that A or B happens. Luckily it is easy to change that into an AND function:

The change that A OR B happens, is 1 - (the change that A doesn't happen AND the change that B doesn't happen).

In your problem: the chance you get greater than 3 OR the chance you get odd number equals
1 - (the chance you don't get greater than 3 AND the chance you don't get an odd number)
= 1 - (the chance you get a number <= 3 AND the chance you get an even number)
This is an AND, so you can multiply them:
= 1 - (the chance you get a number <= 3) * (the chance you get an even number)
= 1 - 0.5 * 0.5 = 0.75

So remember: whenever you get an OR, make it an AND function:
A OR B = 1 - (not A AND not B) = 1 - (probability of not A) * (probability of not B)

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getting a number greater than 3: means getting 4,5,6
getting odd number means getting 1,3,5
so, in any way there are 6 outcomes in all for rolling a die once: 1,2,..6
for each of the events, probability = 3/6 =1/2
if you want the combined probability, it's 5/6!

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For the answer, you would multiply the probability of rolling a number greater than 3 which would be 3/6 or 1/2 simplified by the probability of rolling an odd number which is also 3/6 or 1/2 simplified. Multiply 1/2 x 1/2 which equals 1/4.

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Well, a die has six faces 1-6. 4,5,6 are greater than 3. It says or odd. 1,3,5 are odd. Combine them and you have 1,3,4,5,6. 5/6 numbers are here so your chances are 5/6.

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those numbers are 1, 3, 4, 5, 6 so you have 5 chances out of 6 of rolling one of those numbers or 5:6

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Greater than 3: 1/2 or 50% ( 4, 5, 6 )
Odd Number: Same ( 1, 3, 5 )

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5/6
1
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