We have already done a few Z-tests before where we validated our null hypothesis.
A T-distribution is similar to a Z-distribution—it is centered at zero and has a basic bell shape, but its shorter and flatter around the center than the Z-distribution.
The T-distributions' standard deviation is usually proportionally larger than the Z, because of which you see the fatter tails on each side.
The t distribution is usually used to analyze the population when the sample is small.
The Z-test is used to compare the population mean against a sample or compare the population mean of two distributions with a sample size greater than 30. An example ...