# Draw a Quantile-Quantile Plot in R Programming – qqline() Function

The Quantile-Quantile Plot or (Q-Q Plot) is defined as a value of two variables that are plotted corresponding to each other and check whether the distributions of two variables are similar or not with respect to the locations. `qqline()` function in R Language is used to draw a Q-Q Line Plot.

Syntax: qqline(x, y, col)

Parameters:
x, y: X and Y coordinates of plot
col: It defines color

Returns: A QQ Line plot of the coordinates provided

Example 1: Implementation of Basic QQplot Interpretation

 `# Set seed for reproducibility ` `set.seed``(500) ` ` `  `# Create random normally distributed values ` `x <- ``rnorm``(1200) ` ` `  `# QQplot of normally distributed values ` `qqnorm``(x)  ` ` `  `# Add qqline to plot ` `qqline``(x, col = ``"darkgreen"``) `

Output: Above is a representation of QQplot of Normally Distributed Random Numbers.

Example 2: Implementation of QQplot of Logistically Distributed Values

 `# Set seed for reproducibility ` ` `  `# Random values according to logistic distribution ` `# QQplot of logistic distribution ` `y <- ``rlogis``(800)   ` ` `  `# QQplot of normally distributed values ` `qqnorm``(y)  ` ` `  `# Add qqline to plot ` `qqline``(y, col = ``"darkgreen"``) `

Output: Above is the Q-Q Plot of theoretical quantiles.

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