For certain ore samples, the proportion Y of impurities per sample is a random variable with density function f(y) = 9 2 y8 + y, 0 ≤ y ≤ 1, 0, elsewhere. The dollar value of each sample is W = 7 − 0.7Y. Find the mean and variance of W. (Round your answers to four decimal places.)

What is the equation of a parabola y(x) that has a vertex at point (− 1/3 , 0.3) and passes through point (− 2/15 , − 1/2 ).

(note i put the graph in so plz )the graph shows the amount of water that remains in a barrel after it begins to leak. the variable x represents the number of days that have passed since the barrel was filled, and y represents the number of gallons of water that remain in the barrel. what is the slope of the line

The line plot below represents the number of letters written to overseas pen pals by the students at the waverly middle school.each x represents 10 students. how many students wrote more than 6 and fewer than 20 letters. a.250 b.240 c.230 d.220