BIO318: Statistics Workshop A brief primer on the use of statistics in the study of animal behaviour

BIO318: Statistics Workshop A brief primer on the use of statistics in the study of animal behaviour

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## BIO318: Statistics Workshop A brief primer on the use of statistics in the study of animal behaviour

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**BIO318: Statistics WorkshopA brief primer on the use of**statistics in the study of animal behaviour**Outline**• What is Statistics? • Why do we use Statistics? • Some “simple” guidelines • Overview of the assignment • Useful resources • Questions**What is Statistics?**• “A branch of applied mathematics concerned with the collection and interpretation of quantitative [numerical] data” http://wordnet.princeton.edu/**“Simple” Guidelines**• What is your question? Your hypothesis? • Describe the structure of your data • Graph your raw data • Decide what statistical test to employ • Is your data parametric or not? • Find an appropriate resource to carry out statistical test • Interpret the results of statistical test • Write-up the results and display the summary statistics**“Simple” Guidelines**• What is your question? Your hypothesis? • Describe the structure of your data • Graph your raw data • Decide what statistical test to employ • Is your data parametric or not? • Find an appropriate resource to carry out statistical test • Interpret the results of statistical test • Write-up the results and display the summary statistics**1. Cricket Aggression Experiment**• Question: • What is the effect of female presence on male-male aggression in the house cricket, Acheta domesticus? • Hypothesis: • Female presence affects the aggressive behaviours of male crickets. • Prediction: • During aggressive contests, pairs of males in the presence of a female will behave differently than pairs of males on their own.**“Simple” Guidelines**• What is your question? Your hypothesis? • Describe the structure of your data • Graph your raw data • Decide what statistical test to employ • Is your data parametric or not? • Find an appropriate resource to carry out statistical test • Interpret the results of statistical test • Write-up the results and display the summary statistics**2. Cricket Aggression Raw Data:Aggressive Song Duration (s)**Independent Variable? Dependent Variable? # of IVs? Type of IV? Type of DV?**“Simple” Guidelines**• What is your question? Your hypothesis? • Describe the structure of your data • Graph your raw data • Decide what statistical test to employ • Is your data parametric or not? • Find an appropriate resource to carry out statistical test • Interpret the results of statistical test • Write-up the results and display the summary statistics**3. Graph your raw data**Song Duration (s) Without Fem. With Fem. Treatment • Check for data entry mistakes • Helps you decide on the proper statistical test**3. Graph your raw data**Song Duration (s) Without Fem. With Fem. Treatment • Check for data entry mistakes • Helps you decide on the proper statistical test**3. Graph your raw data**Song Duration (s) Without Fem. With Fem. Treatment • Check for data entry mistakes • Confirms how you thought your data was organized**3. Graph your raw data**Song Duration (s) Without Fem. With Fem. Treatment**3. Graph your raw data**Song Duration (s) Without Fem. With Fem. Treatment**3. Graph your raw data**Song Duration (s) Without Fem. With Fem. Treatment**3. Graph your raw data**Song Duration (s) Without Fem. With Fem. Treatment**3. Graph your raw data**Song Duration (s) Without Fem. With Fem. Treatment**“Simple” Guidelines**• What is your question? Your hypothesis? • Describe the structure of your data • Graph your raw data • Decide what statistical test to employ • Is your data parametric or not? • Find an appropriate resource to carry out statistical test • Interpret the results of statistical test • Write-up the results and display the summary statistics**“Simple” Guidelines**• What is your question? Your hypothesis? • Describe the structure of your data • Graph your raw data • Decide what statistical test to employ • Is your data parametric or not? • Find an appropriate resource to carry out statistical test • Interpret the results of statistical test • Write-up the results and display the summary statistics**With Female**Without Female 4b. Assessing Parametric AssumptionsFrequency Histograms**4b. Assessing Parametric AssumptionsBoxplots**Song Duration (s) Without Fem. With Fem. Treatment**“Simple” Guidelines**• What is your question? Your hypothesis? • Describe the structure of your data • Graph your raw data • Decide what statistical test to employ • Is your data parametric or not? • Find an appropriate resource to carry out statistical test • Interpret the results of statistical test • Write-up the results and display the summary statistics**5. Pick Your Analysis Program**• On-line tools • Statistics software**“Simple” Guidelines**• What is your question? Your hypothesis? • Describe the structure of your data • Graph your raw data • Decide what statistical test to employ • Is your data parametric or not? • Find an appropriate resource to carry out statistical test • Decipher the output of statistical test • Write-up the results and display the summary statistics**6. Deciphering the Output**• Null Hypothesis (H0): • No difference between two categories of IV • Alternative Hypothesis (Ha): • Categories of IV differ from one another If p < 0.05, then reject H0 (i.e. H0 is false, therefore Ha must be true) If p > 0.05, then do not reject H0 (i.e. results inconclusive)**“Simple” Guidelines**• What is your question? Your hypothesis? • Describe the structure of your data • Graph your raw data • Decide what statistical test to employ • Is your data parametric or not? • Find an appropriate resource to carry out statistical test • Decipher the output of statistical test • Write-up the results and display the summary statistics**Song Duration (s)**Without Fem. With Fem. Treatment 7. Summarize Data Results: • clear, concise, objective • do not interpret data • indicate the direction of effect, if any • give test statistics, sample sizes, p-values Figure 1: Give a descriptive caption.**Statistics Assignment**• analyze the six different aggressive behaviours • make sure to use the appropriate parametric or nonparametric test • write a results section • construct figures to display results