Analyzing two variables together

If your dataset has two variables, you have bivariate data. When examining bivariate data, you want to explore possible relationships. This is where good questioning pays off. You can use the following four questions to guide your exploratory data analysis:

• What does the data look like?

• Is there any relationship between two variables?

• Is there any correlation between the two?

• Is the correlation significant?

Four words summarize these questions: Look-Relationships-Correlation-Significance. You will explore pairs of variables from the marketing dataset to investigate these questions using both tabular and graphical exploration methods.

What does the data look like?

This is something you know very well at this point. Summarize the data in your console as shown in the following:

summary(marketing) 

The following is the output:

google_adwords      facebook        twitter       marketing_total 
 Min.   : 23.65   Min.   : 8.00   Min.   :  5.89   Min.   : 53.65  
 1st...