MetSizeR : sim.pilot.data: no visible global function definition for
  ‘rnorm’
MetSizeR : sim.pilot: no visible global function definition for
  ‘rgamma’
MetSizeR : sim.pilot: no visible global function definition for ‘rnorm’
MetSizeR : samp.dist: no visible global function definition for ‘var’
MetSizeR : metsize: no visible global function definition for ‘qnorm’
MetSizeR : metsize: no visible global function definition for
  ‘quantile’
MetSizeR : metsize: no visible global function definition for ‘lm’
MetSizeR : metsize: no visible global function definition for ‘par’
MetSizeR : metsize: no visible global function definition for ‘plot’
MetSizeR : metsize: no visible global function definition for ‘lines’
MetSizeR : metsize: no visible global function definition for ‘abline’
MetSizeR : metsize: no visible global function definition for ‘legend’
MetSizeR : metsize: no visible global function definition for ‘arrows’
MetSizeR : metsize: no visible global function definition for ‘title’
MetSizeR : metsize: no visible global function definition for ‘text’
MetSizeR : pilot.open: no visible global function definition for
  ‘read.table’
MetSizeR : cov.open: no visible global function definition for
  ‘read.table’
MetSizeR : demo.pilot.open: no visible global function definition for
  ‘read.table’
MetSizeR : ssize.est : up.size: no visible global function definition
  for ‘pdf’
MetSizeR : ssize.est : up.size: no visible global function definition
  for ‘dev.off’
MetSizeR : <anonymous>: no visible global function definition for
  ‘help’
Undefined global functions or variables:
  abline arrows dev.off help legend lines lm par pdf plot qnorm
  quantile read.table rgamma rnorm text title var
Consider adding
  importFrom("grDevices", "dev.off", "pdf")
  importFrom("graphics", "abline", "arrows", "legend", "lines", "par",
             "plot", "text", "title")
  importFrom("stats", "lm", "qnorm", "quantile", "rgamma", "rnorm",
             "var")
  importFrom("utils", "help", "read.table")
to your NAMESPACE file.