In statistics, confidence intervals can be used to express the degree to which sample results are reliable.

Confidence intervals are often stated in terms of a percentage like 90% or 95%. When the sample or population distribution is the Normal (bell-shaped) distribution, the confidence intervals can be represented as a number of standard deviations (σ) above or below the sample mean (μ).

Moving the slider beneath the graph will vary the confidence intervals from 50% to 99%. Additionally, you may choose the two-tailed confidence intervals or the one-tailed interval by tapping the button beneath the slider.

In this application, you may chose the standardized Normal distribution with μ=0.0 and σ=1.0 or some other values for mean and standard deviation.