Primary exercises

Create tibble

  1. Create a tibble exercise_group for a group of individuals with names {Sonja, Steven, Ines, Robert, Tim} with their heights {164, 188, 164, 180, 170}, weights {56.0, 87.0, 54.0, 80.0, 58.5} and frequency of exercise {high, high, low, moderate, low}.

tibble subset

  1. Take the tibble exercise_group from the previous exercise and create a new tibble exercise_group_sub without the height and weight variables by selection [.

Extract variables as vectors

  1. Given the tibble favourite_colour, how old were the subjects by the end of 2021?

  2. What is the mean height in exercise_group? Use mean function (see ?mean).

Read tibbles from file

  1. Read pulse.csv data set into R and inspect its dimensions.

  2. Read survey.csv data set into R.

  • Inspect the dimensions.

  • Show the first 9 and the last 7 rows.

  • Calculate the mean age.

  • Calculate the mean height in survey data.

Extra exercises

  1. In survey data:

  1. What is the mean height of the last 30 observations?

  2. The variable age is the last column in the survey data. Make a tibble where the variable age comes directly after name.

  1. Create the favourite_colour tibble from the lecture but now with colour variable as a factor. Print the counts for each level.

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