clt1: no visible global function definition for ‘graphics.off’
clt1: no visible global function definition for ‘curve’
clt1 : <anonymous>: no visible global function definition for ‘dt’
clt1: no visible global function definition for ‘abline’
clt1: no visible global function definition for ‘text’
clt1: no visible global function definition for ‘dt’
clt1: no visible global function definition for ‘var’
clt1: no visible global function definition for ‘dev.new’
clt1: no visible global function definition for ‘dev.set’
clt1: no visible global function definition for ‘hist’
clt1: no visible global function definition for ‘dnorm’
clt1: no visible global function definition for ‘sd’
clt1: no visible global function definition for ‘locator’
clt1 : <anonymous>: no visible global function definition for ‘dnorm’
clt1 : <anonymous>: no visible global function definition for ‘sd’
clt2: no visible global function definition for ‘graphics.off’
clt2: no visible global function definition for ‘curve’
clt2 : <anonymous>: no visible global function definition for ‘dunif’
clt2: no visible global function definition for ‘abline’
clt2: no visible global function definition for ‘text’
clt2: no visible global function definition for ‘var’
clt2: no visible global function definition for ‘dev.new’
clt2: no visible global function definition for ‘dev.set’
clt2: no visible global function definition for ‘hist’
clt2: no visible global function definition for ‘dnorm’
clt2: no visible global function definition for ‘sd’
clt2: no visible global function definition for ‘locator’
clt2 : <anonymous>: no visible global function definition for ‘dnorm’
clt2 : <anonymous>: no visible global function definition for ‘sd’
clt3: no visible global function definition for ‘graphics.off’
clt3: no visible global function definition for ‘curve’
clt3 : <anonymous>: no visible global function definition for ‘dgamma’
clt3: no visible global function definition for ‘abline’
clt3 : f: no visible global function definition for ‘dgamma’
clt3: no visible global function definition for ‘optimize’
clt3: no visible global function definition for ‘text’
clt3: no visible global function definition for ‘var’
clt3: no visible global function definition for ‘dev.new’
clt3: no visible global function definition for ‘dev.set’
clt3: no visible global function definition for ‘hist’
clt3: no visible global function definition for ‘dnorm’
clt3: no visible global function definition for ‘sd’
clt3: no visible global function definition for ‘locator’
clt3 : <anonymous>: no visible global function definition for ‘dnorm’
clt3 : <anonymous>: no visible global function definition for ‘sd’
plot.htest: no visible global function definition for
  ‘normal.and.t.dist’
read: no visible global function definition for ‘vignette’
Undefined global functions or variables:
  abline curve dev.new dev.set dgamma dnorm dt dunif graphics.off hist
  locator normal.and.t.dist optimize sd text var vignette
Consider adding
  importFrom("grDevices", "dev.new", "dev.set", "graphics.off")
  importFrom("graphics", "abline", "curve", "hist", "locator", "text")
  importFrom("stats", "dgamma", "dnorm", "dt", "dunif", "optimize", "sd",
             "var")
  importFrom("utils", "vignette")
to your NAMESPACE file.