Probability Number Line
1
0
Events that are impossible have a probability of 0.
Rolling a 7 with a 6-sided dice.
Rolling a 7 with a 6-sided dice has a probability of 0
because it cannot happen.
Probability Number Line
1
0
Events that are certain have a probability of 1.
Getting wet if you walk out in a downpour with no umbrella.
The probability of you getting wet in this scenario is 1.
It is certain to happen.
Probability Number Line
0
An event whose
probability is closer to
0 is less likely to occur.
1
An event whose
probability is closer to 1
is more likely to occur.
Probability Number Line
1
0
The “red” event
falls on the
number line here.
The “green” event
falls on the
number line here.
What can we say about the probability
of these two events?
Probability Number Line
1
0
The “red” event
falls on the
number line here.
The “green” event
falls on the
number line here.
What can we say about the probability
of these two events?
What is the probability of…
0
½
1
Having a coin land on heads.
What “number” falls in the middle of 0 & 1?
So, the probability of a coin landing on heads is ½.
The coin is just as likely to land on heads as it is to land on
tails. Events that have the same likelihood of happening
fall right in the middle of 0 & 1.
Probability Number Line
0
½
Since we use a number line to express the
probability of events occurring, we can assign
number values to our probabilities.
These number values can take the form of
fractions.
1
Coin Toss
0
½
1
We determined that the probability of a coin
landing on heads is ½, so it would fall on the
number line exactly halfway between 0 & 1.
The fraction
The
gives
us numerator gives
us the total number
information
of the desired
about
outcomes.
event.
½
The denominator
gives us the total
number of all
possible
outcomes.
Writing Probabilities as Fractions
So, let’s come up with the probability for the following:
What would be the fraction you
would write to show the
probability of picking…
Writing Probabilities as Fractions
So, let’s come up with the probability for the following:
What would be the fraction you
would write to show the
probability of picking…
Writing Probabilities as Fractions
So, let’s come up with the probability for the following:
What would be the fraction you
would write to show the
probability of picking…
Writing Probabilities as Fractions
0
½
We can plot our probabilities on the number line too.
Probability of picking…
a yellow letter?
a black letter?
a consonant?
1
Writing Probabilities as Fractions
0
½
We can plot our probabilities on the number line too.
Probability of picking…
king?
a black card?
a diamond?
1