Learning R for Data Visualization (Video 16)

This video tutorial covers how to add lines to plots using GGplot2, focusing on trendlines and fixed lines. It explains the concept of trendlines, including positive and negative correlations, and demonstrates how to add them to scatter plots using the GM_smooth function. The tutorial also shows how to add fixed vertical and horizontal lines to plots, such as histograms, using GM_Vline and GM_Hline functions. The video concludes with a brief overview of the next topic, which is adding text to plots.

What does a positive correlation between two variables indicate?

• Both variables remain constant.

• The variables are unrelated.

• An increase in one variable leads to an increase in the other.

• An increase in one variable leads to a decrease in the other.

Which function is used to add a linear trendline in GGplot2?

• GM_smooth

• GM_plot

• GM_trend

• GM_line

What does the 'SE' option in GM_smooth function stand for?

• Simple Estimate

• Standard Equation

• Standard Error of the Mean

• Smooth Error

Which function is used to add a vertical line in GGplot2?

• GM_Vertical

• GM_Vline

• GM_Line

• GM_Hline

What is the purpose of adding a horizontal line to a plot?

• To indicate a trend

• To mark a specific value like a legal threshold

• To add color to the plot

• To create a border