predict.lm function. RDocumentation. Retrieved from [www.rdocumentation.org/packages/stats/versions/3.6.2/topics/predict.lm](https://www.rdocumentation.org/packages/stats/versions/3.6.2/topics/predict.lm) 

University of Michigan - Ann Arbor

- predict() returns y-hat (estimate) based on your training model. 
- This method produces the confidence and prediction intervals for the prediction of YVAL given a value of the XVAL. In other words, for each training set, we have corresponding x and y values. 
- Now we have a new data set and we are passing a vector with one column from that new data and we want to predict the prediction/confidence intervals for that new data value based on the training data model.
```R
predict(lm.fit, data.frame(XVAL=(c(new_data_row_value1, new_data_row_value2), interval = “”)
#Example: 
predict(lm.fit, data.frame(XVAL=(c(5, 10,15)), interval = “prediction”)
	#Above, data.frame is included as an optional data frame that looks for variables to predict. Without it, fitted values are used.
	#interval = “confidence” , “none”, “prediction” are all options
        ```

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