Probability is a mathematical way of describing the likelihood that a certain event will happen, it
is measured as a number between zero and one where zero means that the event will never happen.
One will mean that event is absolutely going to happen.
And any number in between is a measure that the likelihood that the event will happen let P of a B.
The probability that Event A will occur such that for any event A the probability is between zero and
one.
For example, if the probability is point five, then there's a 50 percent chance that the event will
occur such that on average it will have been half the time that the event is tested.
So if we have our look at a single coin toss, we can even get a heads or tails showing on the up face
utmost face.
So the set of possible events is either heads or tails, and we're going to have a 50/50 chance of getting
either heads or tails.
So at this point, five probability of getting heads and a point, five probability of getting tails.
So if we flip the coin 10 times, it is likely that all heads five times in total and tails five times
in total.
And this is on average.
So if we look at this single toss event, we have a set of heads and tails and we know that there's
a probability of getting point five for heads and a probability of point five for tails.
Now, if we sum them up, we're going to get the total probability and this probability is going to
equal to one.
So this is saying that if we look at all the different events in the city, we're going to get at least
one of the events of the set.
So if we sum up all the events is always going to equal to one.
And we can write this as this.
So the sum of all possibilities for each event or outcome in S must equal one.
So we know that one event has to happen is is impossible not to get any one of those events.
The probability of event occurring, assuming that each event is equally likely, can be written as
this probability equation here.
So the probability of Event A is equal to the number of days event occurs divided by the number of outcomes.
So if we have a look at tossing two coins, we're going to get a heads, heads, heads, tails, a tale
head or tail tails, so we have four different outcomes when we toss Cossey two coins so we can work
out the probability that we're going to get a heads, heads.
So heads, heads, we're going to get we can get it one way.
So the number of times we get that A is one number of events instead.
S is four.
So one, two, three, four.
So the probability of getting heads heads is one of the four and we can do that for the same thing for
all the other probability.
So probability of heads, tails, tails, heads and tails, tails.
And if we have a look at this again, we can see that if we suck up all the probabilities here, it
is going to equal to one.
So we have to get at least one event out of this set occurring.
Since we know that the total probability of all outcomes must equal one, then the probability of event
A not occurring must be given by this relationship here.
So the probability that Event A does not occur must be the total probability, one minus the probability
that event occurs.
So if we look at the example of rolling a single dice, we can even get the outcomes one, two, three,
four, five or six represented by this set here.
So the probability of rolling in two must be one of the six.
There's one way to get a two and there's six different outcomes.
So the probability of going a two is one of the six.
We know the probability of rolling any number between one and six must be equal one because it's all
the different options in the set.
So then the probability of rolling any number other than a two must be the probability of not getting
a two is just one minus probability of getting two or one minus or one minus one, six or five, six.
So the probability of drawing any number of other than two is five over six.
And we can easily see this from the set up here.
If we don't if we want to work out the probability of getting a number, that's not a two is just give
me one, two, three, four, five.
Divided by the total number, which is six.
So to summarize, the total probability of a single set is has to equal to one one outcome must happen
every time we test the four and then the probability of event occurring, assuming that each event is
equally likely, is given by the number of ways even A can occur divided by the total number of outcomes.
So if we're talking about flipping a coin, it'll be 50/50 for heads or tails, assuming the age of
the event is equally as likely.
So the coin is not weighted, so it doesn't have a higher probability of landing on one or the other.
If it did, would need a different way of accounting for this and the probability of event A not occurring
or the probability of not a just equal to one minus the probability of the event occurring.