Probability

Question 1

What is a complementary event in probability?

Answer 1

• In general, two events are complementary if one of the two events must happen and, when it does, the other event can’t.
• The sum of the probabilities of two complementary events must equal 1, this is known as the total probability.

Question 2

What is a permutation

Answer 2

• A permutation is an ordered arrangement of all or part of a set of distinguishable things such that you chose ‘r’ things from ‘n’ distinguishable things.

n
^P
r

Question 3

What is Experimental Probability? What is its formula?

Answer 3

Sayer don’t have enough information to calculate probability, we can do an experiment on say a coin that is biased when we flip it and it prefers tail, we can then calculate the experimental probability by flipping the coin many times, and plugging the results into this formula:

P(E) = Number of ways chosen event occurs/Total number of times experiment is repeated

Question 4

What is theoretical probability? What is it’s formula?

Answer 4

Theoretical probability is when we have enough data about a set of circumstances to calculate the probability of an event occurring. We use the formula P(E) = Number of ways chosen event CAN occur/Total Number of possibilities

Question 5

What is an independent event?

Answer 5

Two events are independent if the occurrence of either one in no way affects the occurrence of the other. For example if an unbiased die is thrown, the outcome of the first throw doesn’t affect the second throw.

Multiplication law for independent events is P(A and B) = P(A) * P(B)