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.
Types of Trees Although region plays a large part in what types of evergreens are available, Dungey finds the most popular varieties are balsam fir, Douglas fir, noble fir, Scotch pine, Virginia pine, and eastern white pine mainly because of how easy they are to grow.