7: Chi Square Analysis
- Page ID
- 171259
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- 7.1: Binomial Distribution
- The binomial distribution predicts the probability of a given number of successes in independent trials with two possible outcomes. Worked examples show how to identify the number of trials and outcome probability, then calculate probabilities for exact counts or ranges of counts.
- 7.2: Phenotypic Ratios May Not Be As Expected
- Observed offspring ratios can differ from genetic predictions because of random sampling or differences in survival. Chi-square testing helps assess whether deviations are consistent with chance variation or suggest that the genetic assumptions need reconsideration.
- 7.3: Goodness-of-Fit Test
- Chi-square goodness-of-fit tests compare observed counts with counts expected under a null hypothesis. Worked examples show how to calculate the test statistic, determine degrees of freedom, and decide whether to reject the predicted distribution.

