Programming in R is organized around functions. You all know what a mathematical function is, like logxor ˚(z) or sin : it is a rule which takes some inputs and delivers a de nite output. A function in R, like a mathematical function, takes zero or more inputs, also called arguments, and returns an output.

List of cross stitch symbolsBy default the function produces the 95% confidence limits. For example, the 95% confidence interval associated with a speed of 19 is (51.83, 62.44). This means that, according to our model, a car with a speed of 19 mph has, on average, a stopping distance ranging between 51.83 and 62.44 ft.

The lattice package, written by Deepayan Sarkar, attempts to improve on base R graphics by providing better defaults and the ability to easily display multivariate relationships. In particular, the package supports the creation of trellis graphs - graphs that display a variable or the relationship between variables, conditioned on one or more ...