The standard deviation of the sound levels from 20 randomly selected spots in our college was 4.1 dBA, while the standard deviation from another 24 randomly selected spots was 7.5 dBA. Set , then we should

Find the pattern and use it to list the nth term in the sequence. 6, 12, 20, 30, 42, 56, the nth term of the sequence is

If square root x = -7, then x= -49 true or false

Apinhole camera is made out of a light-tight box with a piece of film attached to one side and pinhole on the opposite side. the optimum diameter d(in millimeters) of the pinhole can be modeled by d=1.9[ (5.5 x 10^-4) l) ] ^1/2, where l is the length of the camera box (in millimeters). what is the optimum diameter for a pinhole camera if the camera box has a length of 10 centimeters