The general addition law (AQA GCSE Statistics): Flashcards
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Practise the cards
10 cards from this deck
What does P(A) represent in a Venn diagram?
What does P(A) represent in a Venn diagram?
It shows the probability that event A occurs.
How do you calculate P(A or B)?
How do you calculate P(A or B)?
Use P(A or B) = P(A) + P(B) - P(A and B).
If P(A) = 0.4, P(B) = 0.5, P(A and B) = 0.2, find P(A or B).
If P(A) = 0.4, P(B) = 0.5, P(A and B) = 0.2, find P(A or B).
P(A or B) = 0.4 + 0.5 - 0.2 = 0.7.
In a group of 30, 10 own cats, 15 own dogs, 5 own both. P(cats or dogs)?
In a group of 30, 10 own cats, 15 own dogs, 5 own both. P(cats or dogs)?
P(cats or dogs) = (10 + 15 - 5)/30 = 20/30 = 2/3.
What does the intersection in a Venn diagram show?
What does the intersection in a Venn diagram show?
It shows elements common to both events.
Why do we subtract P(A and B) in the formula?
Why do we subtract P(A and B) in the formula?
To avoid double-counting the overlap of A and B.
If 40% own a car, 30% own a bike, and 10% own both, find P(car or bike).
If 40% own a car, 30% own a bike, and 10% own both, find P(car or bike).
P(car or bike) = 0.4 + 0.3 - 0.1 = 0.6.
What is a common mistake in using the general addition law?
What is a common mistake in using the general addition law?
Forgetting to subtract the intersection P(A and B).
How can Venn diagrams help in probability problems?
How can Venn diagrams help in probability problems?
They visually organize events and their relationships.
In a survey of 100, 40 like tea, 50 like coffee, 20 like both. P(tea or coffee)?
In a survey of 100, 40 like tea, 50 like coffee, 20 like both. P(tea or coffee)?
P(tea or coffee) = (40 + 50 - 20)/100 = 70/100 = 0.7.