R Tutorial: Know your data

Key Takeaways

now that we've read our data into our let's start with getting to know it a little better one of the most important things you can do when working with any new data is to learn about how it was collected and do an exploratory data analysis we have been working with the Baker's data from the Great British Bake Off in each episode of the show one Baker is eliminated one wins the technical challenge and one is chosen as star Baker the title of star Baker is based on the Baker's performance across three timed challenges the signature the technical and the showstopper now let's have another look at the Baker's data so far we've printed tables to view them but if you have lots of columns most will be cut off when you print here when we print our Baker's data with ten columns we see that there are four more variables that are hidden to see all the columns we use the function glimpse from the deep hire package the argument for glimpse is the name of your table the glimpse output is a transposed view of your data where each variable appears in rows from top to bottom instead of left to right going across each row glimpse prints the first few observed values for every variable we also see the number of observations and variables at the top you may also want to summarize your data by looking at summary statistics for each variable a quick way to do this is with the skim function from the skim or package like glimpse the argument for skim is the name of your table skim provides statistics for every column depending on the type of variable the results are printed horizontally with one roper variable divided in sections for each variable type let's break down the first section of output summarizing our three character variables for Baker there are no missing values and ten complete observations for each variable the minimum and maximum values refer to string lengths also each value is unique here there are no Baker's with the same name the next sections of the skim output summarize dates the variable last underscored 8 underscore UK is the last date that each Baker appeared on the show in the UK from the men and max values we can tell that our data spans about two years for this series factor there are only three unique values across the 10 observations looking at the top counts series four is the most common the logical column named aired underscore us is true if that Baker appeared in a series that aired in the US and false if not the mean tells us that 70% of the Baker's here were seen by us viewers numeric variables are summarised last in addition to the number of missing and complete values skim returns the means standard deviations and quantiles of the variables a mini histogram is also printed to give you a sense for the distribution of each variable from this skimmed output we know that the average age of these Baker's is 34 and Baker's appeared in anywhere from 1 to 10 episodes with a median of 5 only one of these Baker's was crowned star Baker in their time on the show and they want it twice most Baker's in this table never won the technical challenge but one did win three technical challenges now it's time to put glimpse and skin into practice with our bake-off data