Quiz-10

Short answer solutions

Question: This question has 2 parts.

First, define extrapolation.

Next, explain why extrapolation is dangerous to perform.

Answer: Extrapolation can be defined as predicting a new value of our response that is outside the bounds of our data. This is dangerous because we have no idea if the assumed relationship between our variables holds for values of x and y in which we do not have observed data.

Question: Below is the estimated additive model that we fit in class

$\widehat{\text{flipper length}}=147.563+1.10\ast \text{bill length}-5.25\ast \text{Chinstrap}+17.55\ast \text{Gentoo}$

$$\{\begin{array}{ll}1& \text{if Chinstrap level}\\ 0& \text{else}\end{array}$$ $$\{\begin{array}{ll}1& \text{if Gentoo level}\\ 0& \text{else}\end{array}$$

Report and simplify the model above to only look at the relationship between bill length and flipper length for Adelie penguins.

Answer: $\widehat{\text{flipper length}}=147.563+1.10\ast \text{bill length}-5.25\ast \text{0}+17.55\ast \text{0}$

$\widehat{\text{flipper length}}=147.563+1.10\ast \text{bill length}$