We will focus on the chick weights on day 4 (check the column names of 'chick' and note the numbers). How much does the average of chick weights at day 4 increase if we add an outlier measurement of 3000 grams? Specifically what is the average weight of the day 4 chicks including the outlier chick divided by the average of the weight of the day 4 chicks without the outlier. Hint: use c() to add a number to a vector.
If we were to re-run the experiment many times, and estimate linear model terms (beta-hat) each time, this is called the sampling distribution of the estimates. If we take the standard deviation of all of these estimates from repetitions of the experiment, this is called the standard error of the estimate. While we are not sampling individuals, you can think about the repetition of the experiment that we are "sampling" new errors in our observation of Y.