Class VII

Likelihood

Lesson

Let's look at the likelihood of events occurring. Sometimes we might call likelihood the chance of events occurring, or the probability of events occurring.

We will be using $5$5 key words to describe the likelihood of events occurring:

Impossible
- Impossible means an event will DEFINITELY not happen.
- An example of an impossible event is to roll a $7$7 on a regular die.
Unlikely
- Unlikely means an event could happen, but probably won't.
- An example of an Unlikely event is wining the lottery.
Even Chance
- Even Chance means an event will happen as often as it doesn't happen.
- An example of an event with an even chance is flipping a coin. It is equally likely that it will land on a head or a tail.
Likely
- Likely means an event is more likely to happen than not to happen.
- An example of a likely event is it will likely rain if there are already storm clouds in the sky.
Certain
- Certain means an event will DEFINITELY happen.
- An example of a certain event is that if today is Thursday, it is certain that tomorrow will be Friday.

We can put these words on a scale. An event which is impossible is at one end of the scale. At the opposite end of the scale, is an event which is certain of happening. In the middle are the events that have an even chance of happening.

Look at this video to learn the key words for describing likelihood.

Worked Examples

QUESTION 1

What is the chance of flipping tails with a coin?

Impossible
A
Likely
B
Unlikely
C
Even chance
D
Certain
E

QUESTION 2

A game in a classroom uses this spinner.

A colorful spinner is divided into four equal sectors, each with a numerical value and a distinct color. Starting from the top-left and moving clockwise, the first sector is blue with the number $4$4, followed by an orange sector with the number $7$7, a purple sector with the number $5$5, and finally a green sector with the number $6$6. From the center, a white arrow points to the lower right.

What is the chance of spinning an $odd$ number?
certain
A
even chance
B
impossible
C
likely
D
What is the chance of spinning a $2$2?
likely
A
impossible
B
certain
C
even chance
D
What is the chance of spinning a number less than $8$8?
likely
A
impossible
B
even chance
C
certain
D

QUESTION 3

In a drawer, there are $6$6 pairs of new socks and $5$5 pairs of socks with holes in them.

If a random pair of socks is selected, is it more, less or equally likely that you will select a pair of socks with holes in it?
More likely
A
Equally likely
B
Less likely
C

Outcomes

7.DH.DH.4

Feel of probability using data through experiments. Notion of chance in events like tossing coins, dice etc. Tabulating and counting occurrences of 1 through 6 in a number of throws. Comparing the observation with that for a coin.Observing strings of throws, notion of randomness.