Class interval should always be a whole number and yet in this case we have a decimal number. The solution to this problem is to round off to the nearest whole number. In this example, 2.8 gets rounded up to 3. So now our class width will be 3; meaning that we group the above data into groups of 3 as in the table below.
Skeletons come in a number of forms, each suited for a particular set of lifestyles and environments. Skeletons can be rigid, semirigid, or soft. They can also be external or internal. Vertebrates have internal skeletons, called bony skeletons, which consist mainly of calcified bone tissue. Most invertebrates, such as insects, spiders, and crustaceans, have outer skeletons called exoskeletons.
The Human Skeleton. The human skeleton consists of 206 bones and is divided into two parts: the axial skeleton and the appendicular skeleton. The axial skeleton consists of the bones found around the axis (the imaginary midline of the body) and includes the skull, vertebral column, sternum, and ribs.The appendicular skeleton refers to the bones associated with the appendages and includes the bones in the arms, shoulders, legs, and hips (figure 2.3).he skeletal system provides our bodies with support, protection, and shape. The rib cage and scapula protect vital organs like the lungs, kidneys, and liver found in the thoracic cavity of the body.