For this exercise we will use the data set ChickWeight.
This is one of the data sets that comes with base R. Make sure to read
up on it and its variables with ?ChickWeight.
Each chick should have twelve weight measurements. Use the
dplyr package to identify how many chicks have a complete
set of weight measurements and how many measurements there are in the
incomplete cases. Extract a subset of the data for all chicks with
complete information and name the data set complete. (Hint:
introduce a helper variable consisting of the number of
observations)
In the complete data set introduce a new variable that measures
the weight difference for each chick compared to its day 0 weight. Name
this variable weightgain.
Using the ggplot2 package create side-by-side
boxplots of weightgain by Diet for day 21.
Make sure to xhange the order of the categories in the Diet
variable such that the boxplots are ordered by median
weightgain. Describe the relationship in 2-3
sentences.
Using the ggplot2 package create a plot with
Time along the x axis and weight in the y
axis. Facet by Diet. Use a point layer and also draw one
line for each Chick. Color by Diet. Include
the legend on the bottom (check theme).
Describe the
relationship in 2-3 sentences.
Select the Chick with the maximum weight at
Time 21 for each of the diets. Redraw the previous plot
with only these 4 chicks (and don’t facet).
Compute average daily
weights under each Diet and redraw the plot (using the same structure
and aesthetics as before).
Comment on the results and compare all
the visualizations. Which visualization best captures this data set -
and why?
For the submission: submit your solution in an R Markdown file and (just for insurance) submit the corresponding html/word file with it.