Unit 12 · Lesson 04 · Open-Age

Binomial Experiments & Expected Value

A binomial model requires fixed n, two outcomes, constant p, and independent trials. Mean is np and standard deviation is √[np(1−p)].

Learning objectives

  • Explain the central structure of binomial experiments & expected value using precise mathematical language.
  • Apply the governing relationship and verify results with an alternate representation or substitution.
  • State domain, unit, precision, and context restrictions whenever they affect the result.
  • Analyze a misconception and communicate a correction with evidence.

Essential question: How do counting, probability models, distributions, and sampling support responsible conclusions under uncertainty?

Governing relationship

P(X=k)=C(n,k)p^k(1−p)^(n−k).

A binomial model requires fixed n, two outcomes, constant p, and independent trials. Mean is np and standard deviation is √[np(1−p)].

Worked examples

Read each example, close it, and reconstruct the reasoning independently. Then verify by substitution, graph, table, or alternate method.

n=5,p=0.2, find P(X=2).C(5,2)(0.2)²(0.8)³=0.2048.
Mean for n=80,p=0.35.28.

Guided and independent practice

  1. Check binomial conditions.
  2. Calculate an exact probability.
  3. Find mean and standard deviation.
  4. Create one original example involving binomial experiments & expected value and solve it completely.
  5. Use the Khaemenes Scientific Calculator to verify one result, then document the setup and reasonableness check.
  6. Write a one-paragraph explanation connecting symbolic, graphical, numerical, and contextual representations.

Differentiated pathways

Foundation

Review prerequisite vocabulary, annotate each worked step, complete the first four prompts, and use a table or graph to support symbolic work.

Core

Complete every prompt, explain domain and verification, correct errors, and submit the applied task with clear mathematical communication.

Extended

Generalize the relationship, compare methods, use technology strategically, analyze sensitivity, and create a proof, counterexample, or advanced model.

Application laboratory

Model repeated success/failure trials and interpret expected variation.

Required evidence: defined quantities and units; at least two representations; transparent calculations; verification; one limitation; and a defensible conclusion.

Misconception and correction

Common misconception: Using a binomial model when probability changes from trial to trial.

Write the first invalid step, the governing rule that corrects it, and one counterexample or verification that demonstrates the correction.

Mastery evidence

  • Accurate symbolic work with preserved equivalence.
  • Correct domain, interval, unit, and precision statements.
  • At least one independent verification.
  • A correction explaining why an incorrect approach fails.
  • A clear application conclusion that distinguishes mathematical result from recommendation.

Reflection

What structure did you recognize? Which representation was most useful? What assumption or restriction mattered most? What will you do differently on the next problem?