# maths(statistics)

posted by
**Wong** on
.

it is about the system R or R programme. Can anyone help me about the question? Urgent!

Let X denote the concentration of calcium carbonate (CaCO3) in milligrams per

liter. Following are 20 observations of X:

130.8 129.9 131.5 131.2 129.5 132.7 131.5 127.8 133.7 132.2

134.8 131.7 133.9 129.8 131.4 128.8 132.7 132.8 131.4 131.3

(a) Construct an ordered stem-and-leaf display, using stems of 127, 128,......., 134.

In R, use the stem function.

(b) Find the midrange, range, interquartile range, median, sample mean, and

sample variance.

(c) Draw a box-and-whisker diagram. In R, use the boxplot function.