In a high school graduating class of 100 students, 47 studied mathematics, 61 studied physics, and 25 studied both mathematics and physics. If one of these students is selected at random, find the probability that: a. the student took mathematics or history;
b. the student did not take either of these subjects;
c. the student took history but not mathematics.

Use a calculator to verify that σ(x) = 62, σ(x2) = 1034, σ(y) = 644, σ(y2) = 93,438, and σ(x y) = 9,622. compute r. (enter a number. round your answer to three decimal places.) as x increases from 3 to 22 months, does the value of r imply that y should tend to increase or decrease? explain your answer. given our value of r, y should tend to increase as x increases. given our value of r, we can not draw any conclusions for the behavior of y as x increases. given our value of r, y should tend to remain constant as x increases. given our value of r, y should tend to decrease as x increases.