Normal Distributions

This app lets you explore a normal model for commute times. You can adjust the mean (average commute), the standard deviation (spread of times), and even draw a random sample of commuters. The shaded region shows the proportion of the distribution between two cutoffs. Compare the theoretical probability (area under the curve) with the actual proportion of sample points that fall inside the interval.

Mean: minutes    SD: minutes   

Sample size:

Bounds: 25 min — 35 min

Theoretical shaded area:
Sample proportion in bounds:
Left tail (theory):
Right tail (theory):
Cutoffs (z-scores): ,