Statistics Test Two

  1. Consider the data on car speed/stopping distance. Fit a regression model of the stopping distance for the cars (y) predicted by the speed (x).
    1. Plot the data along with the regression line.
    2. Test for outliers.
    3. Test for influential points.
    4. Test for high leverage points.
    5. Give a 95% confidence interval for the effect of speed on the stopping distance.
  2. Consider the data on Stack loss concerning the loss of ammonia as nitric acid up the smokestack.
    1. Fit the model with stack.loss as the y and the other variables as predictors. Give 90% confidence intervals for each of the slopes.
    2. Construct an added variable for Water.Temp and comment on what you see.
    3. Construct a partial-plus-residual plot for Water.Temp and comment on what you see.
    4. Predict the stack loss for an average (mean) level of Air.Flow and Acid.Conc. and a level of Water.Temp one standard deviation below the mean