The 1-Sample Z conducts a hypothesis test of the mean based on sampled data when the population standard deviation, s is known. It also calculates a confidence interval of the mean. This procedure is based on normal distribution. For larger samples (>30), the sample standard deviation may be used in the absence of the population standard deviation. For smaller samples, make sure the data is drawn from a normal distribution or the t-test may be more appropriate.
|Test||Null Hypothesis, H0||Alternate Hypothesis, H1|
|One-tailed||μ = μ0||μ < μ0 or μ > μ0|
|Two-tailed||μ = μ0||μ ≠ μ0|
where μ is the population mean and μ0 is the hypothesised population mean