Hello Researcher, In this section we will discussed about the most important topic for Research Methodology and it is about “Degrees of Freedom“.
The degrees of freedom are determined by the number of distinct calculations that are possible given a set of information. In the case of a univariate t-test, the degrees of freedom are equal to the sample size (n) minus one. Degrees of freedom (df) The number of observations minus the number of constraints or assumptions needed to calculate a statistical term.
The Z-distribution and the t-distribution are very similar, and thus the Z-test and t-test will provide much the same result in most situations. However, when the population standard deviation (σ) is known, the Z-test is most appropriate. When σ is unknown (the situation in most marketing research studies), and the sample size greater than 30, the Z-test also can be used.
When σ is unknown and the sample size is small, the t-test is most appropriate. Since the two distributions are similar with larger sample sizes, the two tests often yield the same conclusion.
When σ is unknown and the sample size is small, the t-test is used.
This article is based on book and internet. There may be other way to describe Degrees of Freedom.