Lesson Notes By Weeks and Term v4 - JHS 1

Lesson Video

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Performance objectives

• Define probability and its use in daily life.
• Calculate the probability of simple events.
• Express probability as a fraction, decimal, and percentage.
• Solve practical problems involving probability.

Lesson summary

This lesson introduces the concept of chance, or probability. In our daily lives in Ghana, we are always dealing with uncertainty. Will the Black Stars win their next match? Will it rain in Kumasi this afternoon? Will I get the last piece of 'kelewele'? Probability is the branch of mathematics that helps us measure and understand these chances. By learning about probability, we can make smarter predictions and decisions based on data, rather than just guessing. This skill is useful in games like Ludo, in understanding weather reports, and even in simple business decisions.

Lesson notes

a) What is Probability? Probability is a measure of how likely it is that something will happen. It is a number between 0 and 1. A probability of 0 means the event is impossible. (Example: The probability of a goat turning into a car). A probability of 1 means the event is certain. (Example: The probability that the sun will rise tomorrow). A probability of 0.5 or 1/2 means the event has an even chance of happening or not happening. (Example: Tossing a fair coin and getting heads).

We can show this on a probability scale:

(Impossible) 0 --- 0.25 --- 0.5 (Even Chance) --- 0.75 --- 1 (Certain) b) Key Terms to Know Experiment: An action or process where the result is uncertain. *Example:* Tossing a coin, rolling a Ludo die, picking a bead from a bag without looking. Outcome: A single possible result of an experiment. *Example:* When you toss a coin, one possible outcome is "Heads". Another is "Tails". Sample Space (S): The set of *all possible outcomes* of an experiment. We usually write it inside curly brackets `{}`. *Example 1 (Tossing a coin):* The sample space is S = {Heads, Tails}. There are 2 possible outcomes. *Example 2 (Rolling a Ludo die):* The sample space is S = {1, 2, 3, 4, 5, 6}. There are 6 possible outcomes. Event (E): A specific outcome or a set of outcomes that we are interested in. *Example:* When rolling a die, the event could be "rolling a 6" or "rolling an even number". c) The Formula for Calculating Probability

To calculate the probability of an event (E), we use a simple formula: