Probability Calculator
Created by: James Porter
Last updated:
Calculate the probability of events occurring. Enter the number of favorable outcomes and total possible outcomes to get probability, percentage, and odds.
What is a Probability Calculator?
A probability calculator is a tool that helps determine the likelihood of an event occurring. It calculates the ratio of favorable outcomes to the total number of possible outcomes, expressed as a decimal, percentage, or odds ratio.
This calculator is useful for various applications, from basic probability problems to more complex statistical analysis. It helps users understand the chances of different outcomes in games, experiments, and real-world scenarios.
Probability Formulas
The basic probability formula is:
P(E) = n(E) / n(S) Where: P(E) = Probability of event E n(E) = Number of favorable outcomes n(S) = Total number of possible outcomes
Additional calculations:
- Percentage = Probability × 100
- Odds = Favorable outcomes : Unfavorable outcomes
Example Calculation
Let's calculate the probability of rolling a 6 on a standard die:
Favorable outcomes = 1 (only one side shows 6) Total outcomes = 6 (six sides on the die) Probability = 1/6 ≈ 0.167 Percentage = 0.167 × 100 = 16.7% Odds = 1:5 (one way to succeed, five ways to fail)
Common Applications
- Games and Gambling: Calculating odds and expected values
- Statistics: Basic probability analysis and hypothesis testing
- Risk Assessment: Evaluating likelihood of events
- Quality Control: Determining defect probabilities
- Weather Forecasting: Predicting weather events
Sources and References
- Ross, S. M. (2019). A First Course in Probability. Pearson.
- Hogg, R. V., & Tanis, E. A. (2018). Probability and Statistical Inference. Pearson.
- Devore, J. L. (2015). Probability and Statistics for Engineering and the Sciences. Cengage Learning.