using the effective coding(simple coding) in R to calculate the Coefficients for the following dataset and lm formula

```
contrasts(dataframe$batch) <- contr.sum(levels(dataframe$batch))
model<- lm(response ~ time*batch, data=dataframe)
summary(model)
```

this is giving only 2 batch result and 3rd level is missing in the output. how to get the 3rd level coefficients like p-value and t-value. able to find the estimate for level3 negative sum of all other batches estimate.

batch | time | assay |
---|---|---|

1 | 0 | 100 |

1 | 1 | 101 |

1 | 2 | 102 |

1 | 3 | 101 |

1 | 6 | 103 |

1 | 9 | 105 |

1 | 12 | 103 |

2 | 0 | 102 |

2 | 1 | 99 |

2 | 2 | 98 |

2 | 3 | 98 |

2 | 6 | 97 |

2 | 9 | 98 |

2 | 12 | 97 |

3 | 0 | 100 |

3 | 1 | 97 |

3 | 2 | 97 |

3 | 3 | 96 |

3 | 6 | 98 |

3 | 9 | 97 |

3 | 12 | 96 |