class: center, middle, title-slide # Data manipulation ### Olivier Gimenez ### last updated: 2022-05-16 ---  --- ## Motivation We use data from package `palmerpenguins` to familiarize ourselves with data manipulation with the tidyverse. We first load the packages we will need. ```r library(palmerpenguins) library(tidyverse) ``` --- ## Question 1 a. Display the data `penguins`. b. Make sure you understand the columns we have in this dataset. c. Filter out penguins for which sex is missing. d. Select variables species, island, bill_length_mm and body_mass_g. e. Store the new dataset in a dat object. --- ## Question 2 a. How many penguins do we have in the dataset? b. How many species? c. How many islands? d. Count the number of penguins per species. e. Count the number of penguins per species and per island. --- ## Question 3 a. Calculate the overall mean body mass. b. Calculate the mean body mass for each species. c. Calculate the mean of both traits bill length and body mass measured for each species.