extremexi: no visible global function definition for 'as.formula'
extremexi: no visible global function definition for 'lm'
extremexi: no visible global function definition for 'predict'
extremexi: no visible global function definition for 'confint'
extremexi: no visible global function definition for 'par'
extremexi: no visible global function definition for 'plot'
extremexi: no visible global function definition for 'lines'
extremexi: no visible global function definition for 'axis'
extremexi: no visible global function definition for 'abline'
extremexi: no visible global function definition for 'legend'
extremexi: no visible global function definition for 'title'
extremexi: no visible global function definition for 'box'
inflexi: no visible global function definition for 'as.formula'
inflexi: no visible global function definition for 'lm'
inflexi: no visible global function definition for 'predict'
inflexi: no visible global function definition for 'confint'
inflexi: no visible global function definition for 'par'
inflexi: no visible global function definition for 'plot'
inflexi: no visible global function definition for 'lines'
inflexi: no visible global function definition for 'axis'
inflexi: no visible global function definition for 'abline'
inflexi: no visible global function definition for 'legend'
inflexi: no visible global function definition for 'title'
inflexi: no visible global function definition for 'box'
rootxi: no visible global function definition for 'as.formula'
rootxi: no visible global function definition for 'lm'
rootxi: no visible global function definition for 'predict'
rootxi: no visible global function definition for 'confint'
rootxi: no visible global function definition for 'par'
rootxi: no visible global function definition for 'plot'
rootxi: no visible global function definition for 'lines'
rootxi: no visible global function definition for 'axis'
rootxi: no visible global function definition for 'abline'
rootxi: no visible global function definition for 'legend'
rootxi: no visible global function definition for 'title'
rootxi: no visible global function definition for 'box'
Undefined global functions or variables:
  abline as.formula axis box confint legend lines lm par plot predict
  title
Consider adding
  importFrom("graphics", "abline", "axis", "box", "legend", "lines",
             "par", "plot", "title")
  importFrom("stats", "as.formula", "confint", "lm", "predict")
to your NAMESPACE file.