Chance or Probability · JHS3 Mathematics

Lesson notes

Learning Objectives

Indicator: B9.4.2.1.2 - Express the probabilities of the events as fractions, decimals, percentages and/or ratios; e.g. using a tree diagram, table or another graphic organiser

By the end of the lesson, learners can:

Draw a complete probability tree diagram showing both trials for an experiment involving two dependent events without replacement.
Calculate the probability of each branch using the multiplication rule for dependent events, writing each result as a fraction in its simplest form.
Convert each fractional probability into its equivalent decimal, percentage and ratio form correctly.
Use a tree diagram or table to solve word problems involving two dependent events and express the final answers in at least two different forms.
Compare probabilities expressed in different forms (fraction, decimal, percentage, ratio) and determine which form is most helpful in a given situation.

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Curriculum details

Strand: Handling Data (Strand 4)
Sub-strand: Chance or Probability (4.2)
Content standard: B9.4.2.1 - Identify the sample space for a probability experiment involving two dependent events and express the probabilities of given events as fractions, decimals, percentages and/or ratios to solve problems.
Indicator: B9.4.2.1.2 - Express the probabilities of the events as fractions, decimals, percentages and/or ratios; e.g. using a tree diagram, table or another graphic organiser
Suggested placement: Term 3, Week 12 (Week 36 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Curriculum reference: Mathematics, Common Core Programme (JHS1-JHS3), 2023, p. 219
Transcribed from the official NaCCA publication. Check this page against the source.

Exemplars (from the NaCCA curriculum)

E.g. 1 Draw a probability tree diagram for the experiment in B9.4.2.1.1,
E.g. 1. Express the probabilities of the events (on their respective branches) as decimals, percentages and ratios.
E.g. 2:
i. Consider the experiment of drawing two Aces (in two trials) in a standard deck of cards without replacement.
ii. Calculate the probability of each trial and express the probabilities of the events as decimals, percentages and ratios.
E.g. 3:
i. Consider the experiment of drawing an Ace and a Jack (in two trials) in a standard deck of cards without replacement.
ii. Calculate the probability of each trial and express the probabilities of the events as decimals, percentages and ratios.