adjustBeta: no visible global function definition for 'lm'
adjustBeta: no visible global function definition for 'predict'
adjustBeta: no visible global function definition for 'var'
getReturns: no visible global function definition for 'read.delim'
lines.stockReturns: no visible global function definition for 'lines'
lines.testPort: no visible global function definition for 'lines'
pairs.stockReturns: no visible global function definition for 'pairs'
plot.optimalPortfolio: no visible global function definition for 'plot'
plot.optimalPortfolio: no visible global function definition for
  'points'
plot.portReturn: no visible global function definition for 'rgb'
plot.portReturn: no visible global function definition for 'plot'
plot.stockModel: no visible global function definition for 'plot'
plot.stockModel: no visible global function definition for 'text'
plot.stockReturns: no visible global function definition for 'plot'
plot.stockReturns: no visible global function definition for 'lines'
plot.testPort: no visible global function definition for 'plot'
points.optimalPortfolio: no visible global function definition for
  'points'
points.portReturn: no visible global function definition for 'rgb'
points.portReturn: no visible global function definition for 'points'
points.stockModel: no visible global function definition for 'points'
points.stockModel: no visible global function definition for 'text'
points.testPort: no visible global function definition for 'points'
portCloud: no visible global function definition for 'points'
portCloud: no visible global function definition for 'plot'
portPossCurve: no visible global function definition for 'lines'
portPossCurve: no visible global function definition for 'plot'
stockModel: no visible global function definition for 'cov'
Undefined global functions or variables:
  cov lines lm pairs plot points predict read.delim rgb text var
Consider adding
  importFrom("grDevices", "rgb")
  importFrom("graphics", "lines", "pairs", "plot", "points", "text")
  importFrom("stats", "cov", "lm", "predict", "var")
  importFrom("utils", "read.delim")
to your NAMESPACE file.