Basics of the z-test – the z-score, z-statistic, critical values, and p-values
In this section, we will discuss a type of hypothesis test called the z-test. It is a statistical procedure using sample data assumed to be normally distributed to determine whether a statistical statement related to the value of a population parameter should be rejected or not. The test can be performed on the following:
- One sample (a left-tailed z-test, right-tailed z-test, or two-tailed z-test)
- Two samples (a two-sample z-test)
- Proportions (a one-proportion z-test or two-proportion z-test)
The test assumes that the standard deviation is known and the sample size is large enough. In practice, a sample size that is larger than 30 should be considered.
Before going into different types of z-tests, we will discuss the z-score and z-statistic.
The z-score and z-statistic
To measure how far a particular value from a mean is, we could use the z-score or the z-statistic...
