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Chi-square goodness of fit tests

Chi-square goodness of fit tests. Chi-square goodness of fit. Chi-square goodness of fit. Core issue in statistics : When are you viewing just random noise and when is there a real trend?. Chi-square goodness of fit.

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Chi-square goodness of fit tests

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  1. Chi-square goodness of fit tests

  2. Chi-square goodness of fit

  3. Chi-square goodness of fit • Core issue in statistics: When are you viewing just random noise and when is there a real trend?

  4. Chi-square goodness of fit • Core issue in statistics: When are you viewing just random noise and when is there a real trend?

  5. Chi-square goodness of fit • Core issue in statistics: When are you viewing just random noise and when is there a real trend?

  6. Chi-square goodness of fit • Core issue in statistics: When are you viewing just random noise and when is there a real trend?

  7. When to use a chi-square test • Your response variable is count data • Your response falls into different categories • You have a hypothesis for the responses you expect • You want to know if the difference between the responses you observe and the responses you expect is significant or not

  8. How to interpret a chi-square test If the test tells you your data is not significantly different from what you expect, you support the hypothesis If the test tells you your data is significantly different from what you expect, you reject the hypothesis No statistical test ever proves a hypothesis.

  9. What is chi-square? x2 = Chi-square value Σ = Sum of x2 = Σ (Observed Value – Expected Value)2 Expected Value

  10. Example problem #1

  11. Chi-square probability table

  12. Chi-square probability table Only 5% chance that the difference between your obs and exp values comes from chance alone Your hypothesis can be rejected

  13. Chi-square probability table 50-60% chance differences are from random chance

  14. Example problem 2

  15. Female Song Worksheet

  16. Bird song: It’s not just for males anymore Male house wrens sing to attract mates and defend territories Females sing a lot too! Why?

  17. Why do females sing? H1: To help coordinate their behavior with their male Prediction

  18. Why do females sing? H2: To solicit copulations from the male Prediction

  19. Why do females sing? H3: To defend their nests against other house wrens Prediction

  20. Why do females sing? Null hypothesis: Female song occurs randomly Prediction

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