Part 5: Probability

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The Creator

Cards (22)

A table of outcomes is a visual method of showing the possible results of two independent events.
Probability = $\frac{Appearances\ of\ required\ outcome}{Total\ number\ of\ possible\ outcomes}$
Probability represents the chance, or likelihood, of something happening
Relative frequency is an estimate of outcomes using probability and is worked out from trials in an experiment
Something has bias when one outcome is more or less likely to happen than another.
Something is unbiased when each outcome is equally likely to happen.
Mutually exclusive events = events that cannot occur at the same time.
In statistics, a population is the overall group of people, values or items that can be grouped by a common characteristic
Sampling methods make sure that a study avoids bias by choosing the items fairly.
3 main types of sampling:
Random sampling
Systematic sampling
Stratified sampling
Random sampling: each item in the population has an equal chance of being chosen for the sample
Systematic sampling: the population is ordered and items are chosen at regular intervals
Stratified sampling: used when the population can be split into sub-categories (or strata) with the same characteristic
When we take a sample of a population, the size of the sample will affect how representative it is.
A Venn diagram is a visual method of showing the relationship between sets
Intersect in a venn diagram is the overlap between different sets
Union in a venn diagram is the parts in set A or set B or both
The complement of set A on a Venn diagram contains the numbers that are not in set A
Events are independent if the probability of one outcome occurring does NOT affect the probability of another outcome occurring e.g. rolling a dice
Events are dependent if the probability of one outcome occurring DOES affect the probability of another outcome occurring.
AND rule
P(A and B) = $P\left(A\right)\cdot P\left(B\right)$
Events are mutually exclusive if they cannot both happen