Problem # 2 The brake horsepower developed by an automobile engine on a dynamometer is thought to be a function of the engine speed in revolutions per minute ( rpm ) the road octane number of the fuel and the engine compression . An experiment is run in the laboratory and the data that follow are collected Road Brake Octane Horsepower rpm Number Compression 325 2000 90 100 317 1800 94 239 2400 88 10 373 1900 91 96 219 1600 86 100 TO 2500 96 1 10 246 3000 94 98 237 3200 90 100 233 2800 38 105 234 3400 86 97 272 1800 90 100 230 2500 89 104 a ) Fit a multiple linear regression model to the data b ) Test for significance of regression . What conclusions can you draw ( ) Based on t tests do you need all three regressor variables in the model