Mathematics Grade 11 15 min

Calculate probabilities of events

Calculate probabilities of events

Tutorial Preview

1

Introduction & Learning Objectives

Learning Objectives Define and calculate the theoretical probability of a single event. Calculate the probability of the complement of an event using the complement rule. Distinguish between mutually exclusive and non-mutually exclusive events and apply the appropriate Addition Rule to calculate their probabilities. Distinguish between independent and dependent events and apply the appropriate Multiplication Rule. Calculate conditional probabilities using the formula P(A|B) = P(A and B) / P(B). Interpret and solve complex probability problems involving combined events from word problems or data tables. What are the chances your favorite team wins the championship, or that you'll ace your next test? 🏆 Probability is the mathematics of chance! This tutorial will move be...
2

Key Concepts & Vocabulary

TermDefinitionExample Sample Space (S)The set of all possible outcomes of a random experiment.When rolling a standard six-sided die, the sample space is S = {1, 2, 3, 4, 5, 6}. Event (E)A specific outcome or a set of outcomes from the sample space.When rolling a die, the event 'rolling an even number' is the set E = {2, 4, 6}. Complement of an Event (E')The set of all outcomes in the sample space that are not in event E. It represents the event E not happening.If the event is 'rolling a 6' (E = {6}), the complement is 'not rolling a 6' (E' = {1, 2, 3, 4, 5}). Mutually Exclusive EventsTwo or more events that cannot occur at the same time. They have no outcomes in common.When drawing one card from a deck, the events 'drawing a King' and &#03...
3

Core Formulas

The Complement Rule P(A') = 1 - P(A) The probability that an event A will not occur is 1 minus the probability that it will occur. This is useful for calculating the probability of 'at least one' of something happening. The Addition Rule for Probability P(A \cup B) = P(A) + P(B) - P(A \cap B) Calculates the probability that event A OR event B (or both) will occur. If the events are mutually exclusive, P(A \cap B) = 0, and the formula simplifies to P(A \cup B) = P(A) + P(B). The Multiplication Rule for Independent Events P(A \cap B) = P(A) \times P(B) Calculates the probability that two independent events, A AND B, will both occur. To use this, you must confirm the events are independent. The Conditional Probability Formula P(A|B) = \frac{P(A \cap...

4 more steps in this tutorial

Sign up free to access the complete tutorial with worked examples and practice.

Sign Up Free to Continue

Sample Practice Questions

Challenging
If P(A|B) = 0.6 and P(B) = 0.3, what is the value of P(A ∩ B)?
A.0.5
B.2.0
C.0.9
D.0.18
Challenging
A factory has two machines, X and Y. Machine X produces 60% of the items, and Machine Y produces 40%. 2% of items from Machine X are defective, and 3% from Machine Y are defective. What is the probability that a randomly selected item is defective?
A.0.050
B.0.025
C.0.024
D.0.012
Challenging
Two events, A and B, are independent. If P(A) = 2x and P(B) = 3x, and P(A ∩ B) = 0.54, what is the value of x?
A.0.3
B.0.09
C.0.9
D.0.5

Want to practice and check your answers?

Sign up to access all questions with instant feedback, explanations, and progress tracking.

Start Practicing Free

More from Probability

Ready to find your learning gaps?

Take a free diagnostic test and get a personalized learning plan in minutes.