--- title: "ANOVA_Notes_Blank" format: html editor: visual --- ```{r} library(tidyverse) ``` #ANOVA (Analysis of variance) with cuckoos data set An analysis of variance (ANOVA) is a statistical test used to determine whether a continuous and a categorical variable differ. The categorical variable should have three or more groups, or levels. ```{r} library(DAAG) data("cuckoos") ``` Research question: Does egg length differ between the six species? Null hypothesis: $$ H_0: \mu_{\text{hedgesparrow}} = \mu_{\text{meadowpipit}} = \mu_{\text{piedwagtail}} = \mu_{\text{robin}} = \mu_{\text{treepipit}} = \mu_{\text{wren}} $$ Alternative hypothesis: $$ H_a: \text{At least one mean is different } \mu_{\text{species}} \neq \mu_{\text{another species}} $$ ##Visualizing the data ```{r} #box plot ``` ##ANOVA test assumptions - Independence: The data collected is from a representative and randomly selected proportion of the total population. - Normality: The data should be normally distributed - Equality of variances: The variances should be equal across the groups (homoscedasticity). - Outliers: There should be no significant outliers in different groups. ```{r} ``` ##Running the anova ```{r} ``` #ANOVA with the penguins data set ```{r} library(palmerpenguins) ``` Research question: does flipper length differ between species? ##Visualizing the data ```{r} ``` ##Checking assumptions ```{r} ``` ##Running the ANOVA ```{r} ```