In a study concerning the influence of milk on growth, TWO equally sized groups of children are to be given different diets and their growth will be measured. (a) Calculate the number of children in each group that can find a difference of 0.5 cm in a distribution with a standard deviation of 2 cm, with a power of 90%, using a two-sided test at the 1% level (a = 0.01). [Hint: in G*Power choose Test → Means Two independent groups] Effect size = Sample size of each group = Total number of children in the study = (b) If the study only used 500 children, 250 in each group, what would be the power of the study? Power of the study =

A painter weighing 120 pounds is hoisted by means of a rope windlass from the ground to a window on the tenth story of a hotel, 80 feet above ground level. (a) If the weight of the entire rope is considered to be negligible, then find the work W required to lift the person the 80 feet above ground level. (b) Assume that instead of a rope, a substantial chain weighing 2 pounds per foot is used in the windlass. Find the work W1 required to lift the person the 80 feet from ground level. (Hint: Note that as the person is lifted, the length of the chain that must be lifted decreases.)

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Dorothy Wagner is currently selling 80 "I v Calculus" T-shirts per day, but sales are dropping at a rate of 4 per day. She is currently charging $7 per T-shirt, but to compensate for dwindling sales, she is increasing the unit price by $1 per day. How fast, and in what direction, is her daily revenue currently changing? Her revenue is increasing v at a rate of $ per day.