Astudy is being done to test the effects of habitat space on the size of fish populations. aquariums of various sizes are set up with six goldfish in each one. over a period of six months, the fish are fed the same type and amount of food. the aquariums are equally maintained and cleaned throughout the experiment. the temperature of the water is kept constant. at the end of the experiment the number of surviving fish are surveyed. what is the independent variable?

Arnold rossiter is a 40-year-old employee of the barrington company who will retire at age 60 and expects to live to age 75. the firm has promised a retirement income of $20,000 at the end of each year following retirement until death. the firm's pension fund is expected to earn 7 percent annually on its assets and the firm uses 7% to discount pension benefits. what is barrington's annual pension contribution to the nearest dollar for mr. rossiter? (assume certainty and end-of-year cash flows.)