X^2 is not a normal distribution and is always skewed rightwards. DF=# of outcomes - 1.
X^2 = Σ[((O-E)^2)/E].
For X^2 GOF:
1) Check conditions: Each outcome falls into exactly one of a fixed number of categories, You can make hypothesized proportions, SRS, E is 5 or greater in each category
2) State Hypothesis:
Ho: Proportions = model
Ha : At least one proportion not equal to model
3) compute test statistic, Find P-value:
X^2 = Σ[((O-E)^2)/E], then use X^2-cdf, use DF and tail probability (α)
4) reject null hypothesis and write a conclusion about the significance of your evidence