Data on fifth-grade test scores (reading and mathematics) for 420 school districts in California yield y = 646.2 and standard deviation Sy = 19.5

a. Construct a 95% confidence interval for the mean test score in the population.
b. When the districts were divided into districts with small classes (< 20 students per teacher) and large classes (? 20 students per teacher), the following results were found:

Class Size Average y Standard Deviation Sy n
Small 657.4 19.4 238
Large 650.0 17.9 182

Is there statistically significant evidence that the districts with smaller classes have higher average test scores? Explain (set up your hypothesis, and clearly state your decision rule).

Ange in supply or (ii) a movement along the supply curve. a. during a real estate boom that causes house prices to rise, more homeowners put their houses up for sale. b. many strawberry farmers open temporary roadside stands during harvest season, even though prices are usually low at that time. c. immediately after the school year begins, fewer young people are available to work. fast-food chains must raise wages, which represent the price of labor, to attract workers. d. many construction workers temporarily move to areas that have suffered hurricane damage, lured by higher wages. e. since new technologies have made it possible to build larger cruise ships (which are cheaper to run per passenger), caribbean cruise lines have offered more cabins, at lower prices, than before. 2. in the following three situations, the market is initially in equilibrium. after each event described below, does a surplus or shortage exist at the original equilibrium price? what will happen to the equilibrium price as a result? a. in 2010 there was a bumper crop of wine grapes. b. after a hurricane, florida hoteliers often find that many people cancel their upcoming vacations, leaving them with empty hotel rooms. c. after a heavy snowfall, many peop