Statistics · 3rd secondary · First Term

Probability — Calculating probability

About this lesson

This unit introduces the fundamental concepts of probability, starting with the definition of a random experiment and the sample space. It covers how to determine the sample space for experiments such as tossing coins, rolling dice, and drawing balls from a bag, including cases with and without replacement. The unit then defines events (simple, certain, impossible) and operations on events (intersection, union, complement, difference), along with De Morgan's laws and mutually exclusive events. It presents the axioms of probability and important corollaries, such as the addition rule for non-mutually exclusive events. Students learn to calculate probabilities using the formula P(A) = n(A)/n(S) and apply these rules to solve problems involving single and combined events, including real-life applications like exam success and sports team wins. By the end of the unit, students should be able to define sample spaces, identify events, perform set operations on events, and compute probabilities for various scenarios, including those with multiple conditions.

Main topics in this lesson

  • Random experiments and sample spaces
  • Events and operations on events
  • Probability axioms and calculation rules
  • Mutually exclusive events
  • Applications of probability in real-life contexts

Key terms and vocabulary

  • random experiment
  • sample space
  • event
  • simple event
  • certain event
  • impossible event
  • mutually exclusive events
  • intersection
  • union
  • complement
  • difference
  • De Morgan's laws
  • probability
  • probability axioms

Questions and answers on Probability — Calculating probability - practice and revision

Multiple choice questions on this lesson in Statistics for 3rd secondary, First Term, with practice exercises for revision and exam preparation.

1

عند إلقاء حجر نرد مرة واحدة، فإن احتمال ظهور عدد فردي أو عدد أكبر من 4 يساوي:

  • 1 2/3
  • 2 1/2
  • 3 5/6
  • 4 1/3
2

إذا كان احتمال فوز فريق في مباراة هو 0.45، فإن احتمال عدم فوزه يساوي:

  • 1 0.55
  • 2 0.45
  • 3 1
  • 4 0.5
3

إذا كان P(A) = 0.6 و P(B) = 0.5 و A و B حدثان متنافيان، فإن P(A ∩ B) يساوي:

  • 1 0
  • 2 0.3
  • 3 1.1
  • 4 0.1
4

عند إلقاء قطعة نقود مرتين، فإن احتمال ظهور صورة واحدة على الأقل يساوي:

  • 1 3/4
  • 2 1/2
  • 3 1/4
  • 4 1
5

عند سحب كرة واحدة من كيس يحتوي على 3 كرات حمراء و 5 كرات بيضاء، فإن احتمال سحب كرة حمراء يساوي:

  • 1 3/8
  • 2 5/8
  • 3 3/5
  • 4 1/3
6

الحدث الذي يكون احتمال وقوعه مساوياً للواحد الصحيح عند إلقاء حجر نرد مرة واحدة هو:

  • 1 ظهور عدد أقل من 7
  • 2 ظهور العدد 6
  • 3 ظهور عدد فردي
  • 4 ظهور العدد 0

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