Almost all of the students' scores are below the average. Therefore, in this case the mean is not a good representative of the central tendency of this sample. The median, on the other hand, is the value which is such that half the scores are above it and half the scores below. So in this example, the median is 8. There are four scores below and four above the value 8. So 8 represents the mid point or the central tendency of the sample.
Definition of duct. 1 : a bodily tube or vessel especially when carrying the secretion of a gland. 2a : a pipe, tube, or channel that conveys a substanceb : a pipe or tubular runway for carrying an electric power line, telephone cables, or other conductors.
A ductless unit is a split system just like central air, only smaller and more flexible. The compressor sits outdoors and is connected by a pair of refrigerated lines to one or more air handlers inside the house. The hole in the wall for the lines varies, but is usually about 3 inches in diameter.