Lesson Notes By Weeks and Term v4 - SHS 3

PROBABILITY/CHANCE

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  3. SHS 3
  4. PROBABILITY/CHANCE

Subject: Mathematics

Class: SHS 3

Term: 2nd Term

Week: 19

Grade code: 3.4.2.LI.2

Strand code: 4

Sub-strand code: 2

Content standard code: 3.4.2.CS.1

Indicator code: 3.4.2.LI.2

Theme: MAKING SENSE OF AND USING DATA

Subtheme: PROBABILITY/CHANCE

Lesson Video

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Performance objectives

Lesson summary

Probability is the mathematics of chance. It helps us understand and quantify uncertainty in the world around us. From deciding whether to carry an umbrella based on the weather forecast in Accra, to a farmer in the Northern Region planning for planting season, to understanding the risks involved in business ventures, probability is a vital tool for making informed decisions. This lesson focuses on the probability of two events, exploring how the occurrence of one event can sometimes affect the chance of another happening. We will learn the fundamental laws that govern these situations and apply them to solve practical, everyday problems relevant to our lives in Ghana.

Lesson notes

A. Recap: Basic Probability The probability of an event 'A' happening is the ratio of the number of favourable outcomes to the total number of possible outcomes. `P(A) = Number of Favourable Outcomes / Total Number of Possible Outcomes (Sample Space)`

Example: In a box of FanYogo, there are 5 Strawberry and 3 Mango flavours. The probability of picking a Mango flavour at random is: Total outcomes = 5 + 3 = 8 Favourable outcomes (Mango) = 3 `P(Mango) = 3 / 8` B. Independent Events Two events are independent if the outcome of the first event does not affect the outcome of the second event. Think of it as "with replacement" or two completely separate actions.

Key Idea: The sample space remains the same for the second event.

Multiplication Law for Independent Events: If A and B are independent events, the probability that both A and B occur is: `P(A and B) = P(A) × P(B)`

Evaluation guide