# Degrees of Freedom Formula

It is the number of values that remains during the final calculation of a statistic that is expected to vary. In simple terms, these are the date used in a calculation. The degrees of freedom can be calculated to help ensure the statistical validity of chi-square tests, t-tests, and even the more advanced f-tests. Degrees of freedom is commonly abbreviated as ‘df’. Below mentioned is a list of formulas. The number of degrees of freedom refers to the number of independent observations in a sample minus the number of population parameters that must be estimated from sample data.

#### One Sample T Test Formula

\[\LARGE DF=n-1\]

**Two Sample T Test Formula**

\[\LARGE DF=n_{1}+n_{2}-2\]

**Simple Linear Regression Formula**

\[\LARGE DF=n-2\]

**Chi Square Goodness of Fit Test Formula**

\[\LARGE DF=k-1\]

**Chi Square Test for Homogeneity Formula**

\[\LARGE DF=(r-1)(c-1)\]

### Solved Examples

**Question 1: **Find the degree of freedom for given sequence:

x = 2, 8, 3, 6, 4, 2, 9, 5

**Solution: **

Given n= 8

$therefore$ DF = n-1

DF = 8-1

DF = 7

**Question 2: **Find the degree of freedom for given sequence:

y = 18, 21, 32, 43

**Solution:**

Given:

n_{1 }= 6

n_{2 }= 4

Here, there are 2 sequences, so we need to apply

DF = n_{1 }– n_{2 }– 2

DF = 6 -4 -2

DF =0