# Btec stats

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#1
Hi guys
Really stuck on a conditional probability assignment. Just can get my head round it.
A b o blood system.
Four possible groups which a person can belong to: A B AB AND o
In the UK approx A = 45% O = 43% B =9% the rest are AB. In the RH system a person can be said to be either Rh positive or Rh negative. This is approximately Rh positive =85% rh negative 15%
Give answers in as to a decimal fraction

1)What is the probability that a person from the u.k chosen at random will have the blood group AB?

2) what Is the probability that someone from the UK chosen at random will not be in the blood group ab?

3)what is the probability that someone in the UK chosen at random will be either blood group A OR B?

4) the perpetrator of a crime is known to be in blood group AB and be Rh negative. What is the probability that a person from the UK would have this combination!

5) if the probability that someone in the UK is both blood group A and Rh positive is 37%, what is the probability that a person chosen at random is Rh positive, given that the they are of blood group A. give your answer as a % to the nearest integer.

These also have to be drawn as a tree 🎄 diagram.

Any help with this. As deadline next week. I.jusy can't seem to grasp it.

Thanks guys!
0
3 years ago
#2
(Original post by Bobo71)
Hi guys
Really stuck on a conditional probability assignment. Just can get my head round it.
A b o blood system.
Four possible groups which a person can belong to: A B AB AND o
In the UK approx A = 45% O = 43% B =9% the rest are AB. In the RH system a person can be said to be either Rh positive or Rh negative. This is approximately Rh positive =85% rh negative 15%
Give answers in as to a decimal fraction

1)What is the probability that a person from the u.k chosen at random will have the blood group AB?

2) what Is the probability that someone from the UK chosen at random will not be in the blood group ab?

3)what is the probability that someone in the UK chosen at random will be either blood group A OR B?

4) the perpetrator of a crime is known to be in blood group AB and be Rh negative. What is the probability that a person from the UK would have this combination!

5) if the probability that someone in the UK is both blood group A and Rh positive is 37%, what is the probability that a person chosen at random is Rh positive, given that the they are of blood group A. give your answer as a % to the nearest integer.

These also have to be drawn as a tree 🎄 diagram.

Any help with this. As deadline next week. I.jusy can't seem to grasp it.

Thanks guys!
What have you tried? 1) is just the probability that a person in the UK has any blood type - probability it's A - probability it's B - probability it's O. What does that give you?
0
3 years ago
#3
Im doing this assignment too, its for tomorrow . Did you get anywhere with it??
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