Answer Happy

Use the "gala" data from the faraway package in R. Use the boxcox function from the MASS package to perform the the following: - Produce a log-likelihood plot for the Box-cox transformation of the savings data Read of the 95% confidence interval for Use the 95% confidence interval for λ to check whether the response needs transformation.
> library (faraway) > data (gala) > help (gala) Endemics, data = gala) > fit < 1m (Species. > summary (fit) Consider a linear model using Species as outcome and the remaining covariates except from Endemics (which is an alternative response variable in the dataset) as covariates. Note: Since the outcome is a count variable, normality assumptions cannot be met exactly, but will hold approximately for large means due to the central limit theorem. A Poisson regression is the standard GLM approach (not requiring normality), but here we focus on ordinary linear models to study the transformation aspect.