Hildegard, an intelligent and charming Holstein cow, grazes in a very large, mostly barren pasture with a few patches of lush grass. When she finds a new grassy area, the amount of grass she gets from it is equal to the square root of the number of hours, h, that she spends grazing there. Finding a new patch of grass on which to graze takes her 1 hour. Since Hildegard does not have pockets, the currency in which her costs are measured is time. a. What is the total cost to Hildegard of finding a new plot of grass and getting y units of grass from it? b. Find an expression for her marginal costs and her average cost per patch of grass as a function of the amount of grass she gets from each patch. c. How much time would she spend in each plot if she wanted to maximize her food intake? (Hint: Minimize average costs per unit of grass eaten.)

Alarge university wanted to study the relationship between completing an internship during college and students' future earning potential. prom the same graduating class, they selected a random sample of 80 students who completed an internship and 100 students who did not complete an internship and examined their salaries five years after graduation. they found that there was a statistically higher mean salary for the internship group than for the noninternship group. which of the following interpretations is the most appropriate? a. there could be a confounding variable, such as student major, that explains the difference in mean salary between the internship and no internship groups. b. we cannot infer anything from these data since the distribution of salaries is likely right skewed. c. you cannot draw any valid conclusions because the sample sizes are different. d. more students should complete internships because having an internship produces a higher salary.