Confidence Interval Calculator

Confidence Interval for the population means when the standard deviation is known.

Confidence level, usually written as 100%, on the interval estimate of a population parameter is the probability that the interval estimate will contain the true population parameter.  When

Value of z for different values of

Confidence Interval		z
80%	0.200	1.282
85%	0.150	1.440
90%	0.100	1.645
95%	0.050	1.960
99%	0.010	2.576
99.5%	0.005	2.807
99.9%	0.009	3.291