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Normal Probability Calculator

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About This MicroSim

Calculate probabilities for normal distributions with interactive visualization.

How to Use

  • Select query type: P(X < a), P(X > a), or P(a < X < b)
  • Drag the orange marker(s) to change boundary values
  • Adjust μ and σ sliders to change distribution parameters
  • See both z-scores and probabilities update in real time

Key Insights

  • Left-tail probability P(X < a): Area from negative infinity to a
  • Right-tail probability P(X > a): Area from a to positive infinity
  • Between probability P(a < X < b): Area between two values
  • Probabilities are shown as both decimals and percentages
  • Z-scores show how many SDs each value is from the mean

Lesson Plan

Learning Objective

Students will calculate and interpret probabilities from normal distributions using the standard normal curve (Bloom's Taxonomy: Applying, Analyzing).