When analysing normally distributed data, standard deviation can be used in conjunction with the mean in order to calculate data intervals. If = mean, S = standard deviation and x = a value in the data set, then. 1  about 68% of the data lie in the interval: . 2  about 95% of the data lie in the interval: + 2S.
Little gem arborvitae (Thuja occidentals 'Little Gem') is an evergreen shrub that keeps its brilliant color and foliage all year long. Growing 1 to 3 feet tall, little gem has medium texture and a slow growth rate. The dense dwarf shrub has a compact form and globose shape.
The list might include evergreen trees of hollies, cherry laurel, tree ligustrum, loquat, myrtle oak, sand live oak, and sweet acacia plus deciduous selections of Chinese elm, red bud, river birch and winged elm. Most of these grow less than 40 feet tall and not as wide.