About what percentage of the area under the normal dis- tribution curve falls within 1 standard deviation above
and below the mean? 2 standard deviations? 3 standard
deviations?

The decibel level of sound is 50 db greater on a busy street than in a quiet room where the intensity of sound is watt/m2. the level of sound in the quiet room is db, and the intensity of sound in the busy street is watt/m2. use the formula , where is the sound level in decibels, i is the intensity of sound, and is the smallest sound intensity that can be heard by the human ear (roughly equal to watts/m2).

The line containing the midpoints of the legs of right triangle abc where a(-5,5), b(1, 1), and c(3, 4) are the vertices.

How can the correlation in the scatter plot graph below best be described? positive correlation negative correlation both positive and negative no correlation