Stats - Probability

Question 1

What is probability?

Answer 1

The likelihood of an event occurring: P(x)

Question 2

P(x)

Answer 2

The probability of x occurring

Question 3

A probability of 0

Answer 3

Means the outcome can never happen

Question 4

A probability of 1

Answer 4

Means we are certain the outcome will happen

Question 5

Probabilities of all outcomes

Answer 5

Must add up to 1

Question 6

Experiment

Answer 6

Any observation or measurement of a random phenomena eg. tossing a coin

Question 7

Outcomes

Answer 7

The possible results of an experiment

Question 8

Sample space (s)

Answer 8

The set of all possible outcomes or results of an experiment e.g. flipping a coin is heads/tails

Question 9

Types of probability

Answer 9

Subjective, Theoretical, Experimental

Question 10

Subjective probability

Answer 10

Based on experience and intuition eg. Sony is a good brand so “odds are good that…”

Question 11

Theoretical probability

Answer 11

Based on knowing all the likely outcomes of an experiment (ie. rolling a dice is 1/6 chance of rolling a 4)

Question 12

P (event)

Answer 12

Number of favourable outcomes/total # of outcomes possible

Question 13

Uniform probability distribution

Answer 13

P(x) Probability of each outcome

Question 14

Experimental probability

Answer 14

Based on the repetitions of an actual experiment resulting in relative frequencies

Question 15

Relative frequencies

Answer 15

Applies to events that can be repeated over and over again eg. How many students on campus eat poutine for lunch eg. P (eating poutine)

Question 16

Complement of an Event

Answer 16

All outcomes that are not the event eg. If the event is Heads the complement is Tails. Together the event and the compliment make all possible outcomes.

Question 17

Probability Independence

Answer 17

If two events occur and the outcome of one does not in any way influence the outcome of the other, the events are independent. Eg. Rain + Smoking