The normal distribution
A shaded interval under a probability density gives an answer, not just a picture.
Probability under the bell curve
Move the slider to change a symmetric interval around the mean of a standard normal distribution. The shaded area is its probability.
Lower z-score−1.96
Upper z-score1.96
Probability within interval95.0%
This is the probability for a standard normal random variable—not the probability that an unknown parameter lies inside a confidence interval.