A statistical method to determine if observed data fits an expected pattern. Perfect for testing genetic ratios, population distributions, and biological hypotheses.
The Formula
χ² = Σ[(O - E)² / E]
Where O = Observed value and E = Expected value
Degrees of freedom: df = n - 1
Four Steps to Success
1
Calculate expected values from ratios
2
Compute each (O-E)²/E term
3
Sum terms for χ² value
4
Compare to critical value
How to Use This Activity
• Fill in expected values in the table
• Calculate each term with instant feedback
• Make your hypothesis decision
• View detailed solutions when needed
Remember!
Rejecting H₀ means the data does NOT fit the expected pattern. Accept H₀ when χ² < critical value.