There is a government-sponsored study of student achievement in large urban school districts. They give a reading test scored from 0 to 500. A score of 232 is a "basic" reading level and a score of 270 is "proficient." Scores for a random sample of 1400 eighth-graders in a city had x = 237 with standard error 1.0. We don't have the 1400 individual scores, but use of the t procedures is surely safe. Why?

A. Test scores are always normally distributed.

B. A random sample should be normally distributed.

C. The sample size is very large, so the only potential hazard is extreme skewness.

D. A small sample size of a simple random sample should be normally distributed.

1. an economy consists of three workers: larry, moe, and curly. each works 10 hours a day and can produce two services: mowing lawns and washing cars. in an hour, larry can either mow one lawn or wash one car; moe can either mow one lawn or wash two cars; and curly can either mow two lawns or wash one car. a. calculate how much of each service is produced under the following circumstances: a. all three spend all their time mowing lawns. b. all three spend all their time washing cars. c. all three spend half their time on each activity d. larry spends half of his time on each activity, while moe only washes cars and curly only mows lawns b. using your answers to part a, draw a production possibilities frontier and label points a, b, c, and d on your graph. explain why the production possibilities frontier has the shape it does. c. are any of the allocations calculated in part a inefficient? explain.