The chi-square distribution is the sum of standard normal distribution(s) squared. The degrees of freedom for a chi-square distribution is how many standard normal distribution(s) squared you are summing.
Normal Distribution with mean '
' and standard deviation '
So Chi-Square Distribution with k degrees of freedom:
Chi-Square distribution hypothesis testing comes in handy for seeing whether the observed value of some experiment fit the expected values.
observed data point
estimated data point
The critical value is found by looking at the Chi Distribution table