<- lm(bill_length_mm ~ bill_depth_mm * species,
species_lm data = penguins)
Revision Deadlines
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Fit the different slopes (interaction) model
term | Df | Sum Sq | Mean Sq | F value | Pr(>F) |
---|---|---|---|---|---|
bill_depth_mm | 1 | 561.5708 | 561.570850 | 93.96508 | 9.384795e-20 |
species | 2 | 7460.3201 | 3730.160057 | 624.15060 | 7.116342e-114 |
bill_depth_mm:species | 2 | 134.2515 | 67.125732 | 11.23184 | 1.897629e-05 |
Residuals | 336 | 2008.0631 | 5.976378 | NA | NA |
The interaction line of the ANOVA table is testing:
\(H_0\): the slopes for the relationship between bill length and bill depth is the same for all Gentoo, Adelie, and Chinstrap penguins
\(H_A\): the slopes for the relationship between bill length and bill depth is different for at least one species of penguin
bill_depth_mm:species
: With a p-value of 0.0000189, I would reject the null hypothesis (that the slopes are all the same) and I would conclude that there is evidence that the slopes are different!
Suppose, the p-value for bill_depth_mm:species
was 0.45.
What model would be “best” in this scenario?
No! Only if you have 3 or more groups!
Complete these steps before Tuesday’s class to be prepared!
Yes
No
Your Introduction should at a minimum address the following questions:
Research Question
You can hold off on a research question until we learn more about ANOVA next week!
This will be posted by Friday!
These will be posted by Friday!
What is the relationship between life expectancy and GDP per capita?
Step 1: One member of your group needs to follow these instructions to copy the Lab 8 project into your group’s workspace
Step 2: Both members open the Lab 8 assignment in your group workspace!
Step 4: Follow the final instructions to activate collaborative editing in the document.
Source Editor
You need to be in the source editor (not the pretty one) to use collaborative editing!
Roles
You will be trading off roles in the middle of the lab! One person will do the model condition coding and one person will do the hypothesis test coding!