qqplot

qqplot(x::AbstractVector{AbstractFloat}, y::AbstractVector{AbstractFloat}; kwargs...)

The qqplot function compares the quantiles of two distributions.

• qqline: determines how to compute a fit line for the Q-Q plot. The options are

  • identity: draw the line y = x (the deafult).
  • fit: draw a least squares line fit of the quantile pairs.
  • fitrobust or quantile: draw the line that passes through the first and third quartiles of the distributions.
  • none: do not draw any line.

  Broadly speaking, qqline=:identity is useful to see if x and y follow the same distribution, whereas qqline=:fit and qqline=:fitrobust are useful to see if the distribution of y can be obtained from the distribution of x via an affine transformation.

• For fine setting of the line and scatter points use the same options as in the plot module.

Examples:

qqplot(randn(100), randn(100), show=true)

qqplot(randn(100), show=true)