Probability Calculator

Category: Statistics

Probability of Two Events

This calculator determines the probabilities of union, intersection, and other outcomes involving two independent events A and B.

Restrictions: Please input values between 0 and 1 for both P(A) and P(B).

Probability Solver for Two Events

This calculator determines missing probabilities when two independent events A and B are partially defined (e.g., given P(A) and P(A∩B)).

Restrictions: Please input values between 0 and 1 for P(A) and P(A∩B). Ensure P(A∩B) ≤ P(A).

Probability of a Series of Independent Events

This calculator computes probabilities for independent events repeated multiple times, such as the likelihood of success or failure over a sequence of trials.

Restrictions: Please input values between 0 and 1 for probabilities and positive integers for repeat times.

Probability of a Normal Distribution

This calculator computes the probability of a random variable falling within a specified range under a normal distribution.

Restrictions: The standard deviation (σ) must be greater than 0. The left bound must be less than or equal to the right bound.

A Full Probability Calculator Suite

This guide provides a clear explanation of how to use the Probability Calculator Suite effectively. With four distinct calculators, you can solve a wide range of probability problems, from basic event probabilities to advanced scenarios involving normal distributions. These tools are designed to help you calculate and understand probabilities in various contexts with ease.

1. Probability of Two Events

This calculator helps you determine probabilities related to two independent events, A and B. Whether you want to calculate the union, intersection, or complementary probabilities, this tool has you covered.

How to Use:

  1. Enter the probability of Event A (P(A)) in the first input field.
  2. Enter the probability of Event B (P(B)) in the second input field.
  3. Click the Calculate button to view the results, including:
  4. P(A∩B): Probability of both A and B occurring.
  5. P(A∪B): Probability of either A or B occurring.
  6. P(A only) and P(B only): Probabilities of A or B happening individually without the other.
  7. View the visual representation of probabilities in the Venn diagram.

Key Points:

  • Input values for P(A) and P(B) must be between 0 and 1.
  • Results include complementary probabilities like P(A') and P(B').

2. Probability Solver for Two Events

If you have partial data for two independent events (e.g., P(A) and P(A∩B)), this calculator can fill in the gaps and provide missing probabilities.

How to Use:

  1. Enter the probability of Event A (P(A)) in the first input field.
  2. Enter the probability of the intersection of A and B (P(A∩B)) in the second input field.
  3. Click the Calculate button to generate results such as:
  4. P(B): Probability of Event B.
  5. P(A∪B): Probability of either A or B occurring.
  6. P(A△B): Probability of symmetric differences (A or B, but not both).
  7. Verify that P(A∩B) is less than or equal to P(A).

Key Points:

  • Ensure valid inputs where P(A∩B) ≤ P(A).
  • The results provide insights into both combined and complementary probabilities.

3. Probability of a Series of Events

This calculator is ideal for determining probabilities over multiple trials of independent events. For example, it can calculate the likelihood of repeated successes or failures.

How to Use:

  1. Enter the probability of Event A and the number of times it repeats.
  2. Enter the probability of Event B and the number of times it repeats.
  3. Click the Calculate button to view results, such as:
  4. P(A occurring all times): Probability of A happening in every trial.
  5. P(A NOT occurring all times): Complementary probability for Event A.
  6. P(Either A or B occurs): Combined probability over all trials.
  7. P(Both A and B occur): Joint probability across all repetitions.

Key Points:

  • Probabilities should range between 0 and 1, and repeat counts must be positive integers.
  • The results are useful for scenarios like quality checks or success rates in experiments.

4. Probability of a Normal Distribution

This calculator computes the probability of a random variable falling within a specific range in a normal distribution. It is helpful for analyzing data in fields like finance, research, and quality control.

How to Use:

  1. Enter the mean (µ) and standard deviation (σ) of your dataset.
  2. Specify the left bound and right bound of the range.
  3. Click the Calculate button to obtain results, including:
  4. Z-scores for the left and right bounds.
  5. The probability of the variable falling within the specified range.
  6. View a visual chart showing the probability density function (PDF) with the selected range highlighted.

Key Points:

  • Standard deviation (σ) must be greater than 0.
  • Ensure the left bound is less than or equal to the right bound.

General Tips for Using the Calculators

  • Input Validation: Double-check your inputs to ensure they fall within the required ranges.
  • Clear Results: Each calculator provides detailed results in both numeric and visual formats.
  • Reset Buttons: Use the reset button to clear inputs and start over with fresh data.
  • Interactive Visuals: Charts and diagrams make it easy to interpret complex probabilities at a glance.

Why Use This Calculator Suite?

  • Simplify Probability Calculations: Perform complex probability operations without needing advanced math skills.
  • Visualize Data: Gain insights through charts and diagrams.
  • Versatile Tools: Solve problems ranging from basic events to distributions and series.

With this guide, you can confidently use the Probability Calculator Suite to solve a variety of probability challenges with precision and ease.