# Test Equality of Curves with Homoscedastic or Heteroscedastic Errors.

### Description

Fit the smoothing curves.

### Usage

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### Arguments

`formula` |
A formula to the data set such as y~x. |

`data` |
A data frame of 2 columns representing the underlying curve. The column names must agree with the names in formula. |

`alpha` |
Smoothing parameter. Default=0.5. |

`bw` |
Window bandwidth for fitting the curve. |

`kernel` |
One of the kernel functions to use to fit the curves. Must be one of "Triangle", "Gaussian", "Trio","Uniform", "Triweight", "Epanechnikov", "Quartic". partial match is allowed. |

`myx` |
x-values in the test domain to calculate the curve values. |

`bcorrect` |
Boundary correction method. Right now, except for 'none', meaning no corrections, the only other opton is 'simple'. |

`getit` |
unused for this function. |

`add` |
logical, Tf true, add the curves to the plot.Otherwise, add fitted lines to the plot. |

`get.data` |
logical, not used in this function. |

`x` |
The fitted results from fitting the first or second curve by curvefit procedure. |

`y` |
dummy variable for compatible with parameters in the base definition of plot. |

`...` |
parameters for plot such as pch, lty, col etc. |

### Details

For a 2 column data, the curve will be fitted according to formula using local regression method. Boundary corrections can be made. The fitted result will be returned as a 'curvefit' object, that can be plotted and printted by the associated S3 method print and plot.

### Value

An R object of class 'curvefit' will be generated including the fitted values of the curves with original specification of parameters.

### Author(s)

Zhongfa Zhang, Jiayang Sun

### References

Zhongfa Zhang, et al: Test Equality of Curves with Homoscedastic or Heteroscedastic Errors. To appear

### See Also

curvefit, print.curvetest, plot.curvetest

### Examples

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