A t-test for population means compares the means between two populations. It is appropriate when the population standard deviations are unknown. This applet allows users to change the distributions of ...

He was able to use the sample statistics to estimate the population parameter for the mean. By adding and subtracting the value for the Confidence Level (2.199) he computed a confidence interval ...

The long run behavior of a 95% confidence interval is such that we’d expect 95% of the confidence intervals estimated from repeated independent sampling to contain the true population parameter.The ...

A larger random sample will always provide a mean that is closer to the mean of the population. How SEM and Standard Deviation Are Used Both standard deviation and SEM are widely used in ...

A two-sample z-test for population means compares two population means. It is appropriate when the population standard deviations are known and the sample sizes are large. This web calculator conducts ...