The eight subjects used for this comparison were not a random sample. In fact, they were friends of the researchers whose ages and weights were similar to the types of people who would be measured with this DXA. Comment on the appropriateness of this procedure for selecting a sample, and discuss any consequences regarding the interpretation of the significance testing and confidence interval results.

The sample may be a representative of the future of the future subjects, but the test results and confidence interval are suspect  because it is not a random sample

Step-by-step explanation:

When the subjects used for a research are not a random sample but friends whom share similar qualities/quantities related to the purpose of the experiment. The sample may be a representative of the future subjects, but the test results and confidence interval will not be reliable enough to be accepted as standard simply  because it was not a random sample

Hence the comment :The sample may be a representative of the future of the future subjects, but the test results and confidence interval are suspect  because it is not a random sample

To find the area, we need to find the height of the triangle. We are given two sides of the small right triangle, where the hypotenuse is also the short side of the obtuse triangle. Find the perimeter of the triangle in Example A. To find the perimeter, we need to find the longest side of the obtuse triangle.
http://www.saylor.org/site/wp-content/uploads/2013/09/K12MATH007-Area-and-Perimeter-of-Triangles.pdf