W1 self test

Welcome to the PSYC3361 coding W1 self test. The test assesses your ability to use the coding skills covered in the Week 1 online coding modules.

In particular, it assesses your ability to…

choose packages/functions
read in data
group_by and summarise
make notes using RMarkdown
insert pictures in an Rmd document
write data to csv

It is IMPORTANT to document the code that you write so that someone who is looking at your code can understand what it is doing. Above each chunk, write a few sentences outlining which packages/functions you have chosen to use and what the function is doing to your data. Where relevant, also write a sentence that interprets the output of your code.

Your notes should also document the troubleshooting process you went through to arrive at the code that worked.

For each of the challenges below, the documentation is JUST AS IMPORTANT as the code.

Good luck!!

Jenny

1. customise your Rmd document by adding your name as the author, a table of contents and choosing a theme that you like.

2. load the packages you will need

library(tidyverse)

3. read the birthweight data

frames <- read_csv("data/birthweight_data.csv")

4. calculate the mean birthweight separately for twins and singletons

by_plurality <- frames %>%
  group_by(plurality) %>%
  summarise(
    mean_birthweight = mean(birthweight)
  ) %>% 
  ungroup()

5. identify the earliest (i.e. the minimum value) gestational age for each ethicity group

by_ethnicity <- frames %>%
  group_by(child_ethn) %>%
  summarise(
    min_gestational_age = min(gestation_age_w)
  ) %>% 
  ungroup()

6. write some notes about how group_by and summarise work with the pipe below, including a link to documentation or a blog post that you think is useful

the pipe function (%>%) is equivalent to a “then” command. The above code translates to:

“let’s call this new frame”by_ethnicity” (grouped by ethnicity)
obtain the dataset (frames), then group by ethnicity, then summarise/extract the minimal gestational age of each group (and lets call this variable “min_gestational_age”)

I’m not sure what sort of documentation or blog post will be useful? Here are Danielle Navarro’s R tutorials, which should be very helpful.

7. download a picture of a baby from the internet and insert it into your document below

8. write the summary of mean birthweight by twins/singletons that you made in step 3 above to a new csv file

write_csv(by_plurality, file = "mean_birthweight_summary.csv")