Normal Distribution Probability Calculator
Given the mean and standard deviation, find P(X < b), P(X > a) or P(a < X < b) with z-scores.
Step-by-step guides
- How to Use the Normal Distribution to Find ProbabilitiesLearn to use the normal distribution by standardizing values to z-scores, finding cumulative probabilities, and checking whether the model fits.
- Continuity Correction vs. Confidence Interval: What’s the Difference?A continuity correction improves normal approximations to discrete probabilities; a confidence interval estimates an unknown parameter. Here is when each applies.
- How Does a Poisson Distribution Converge to Normal?As a Poisson mean λ grows, centering by λ and scaling by √λ gives a standard normal limit; use a continuity correction for count probabilities.
- Given the Mean and Standard Deviation, How Do You Find a Probability?Convert values to z-scores and use the standard normal table to find P(X < b), P(X > a) and P(a < X < b) from a mean and standard deviation, with examples.