This is one of the most frequently asked data visualization in R coding interview questions and answers for freshers in recent times. When we use plot(airquality) without selecting any particular column or set of columns and when all variables or columns are taken into consideration, then the above chart is displayed. It is a matrix of scatterplots which is nothing but a correlation matrix of all columns in the dataset. Some key inferences are: If we observe the data representations here, ozone and temperature are correlated positively. Wind speed is negatively correlated to both ozone and temperature.