A researcher is testing the claim that the average university student works less then 15 hours a week. To test this claim she surveys a random sample of 20 undergraduate students who reported an average of 13.5 hours a week of work. We will assume that the population is normally distributed with a standard deviation of 5 hours per week. Test this claim at the alpha of 0.02 by calculating the z-score and comparing it to the critical z-score (z subscript c r i t end subscript equals negative 2.05 right parenthesis.

You have the standard error of the mean, so solve for the z-score.

Paula makes stained-glass windows and sells them to boutique stores. if her costs total $12,000 per year plus $4 per window for the frame. how many windows must she produce to earn a profit of at least $48,000 in one year if she sells the windows for $28 each? 1. define a variable for the situation. 2. write an inequality that represents her profit. note: revenue is money coming in. cost is money going out. profit is the difference between the revenue and the cost. in other words: revenue - costs profit 3.using words, describe how many windows she must sell to have a profit of at least $48,000.