1. A simple random sample of five months of sales data provided the following information
Month 1 2 3 4 5
Units Sold 94 100 85 94 92
a. Develop a point estimate of the population mean number of units sold per month.
b. Develop a point estimate of the population standard deviation
2. The College Board reported the following mean scores for the three parts of the Scholastic Aptitude Test (SAT) (The World Almanac, 2009):
Critical Reading 502
Mathematics 515
Writing 494
Assume that the population standard deviation on each part of the test is o = 100.
a. What is the probability a random sample of 90 test takers will provide a sample mean test score within 10 points of the population mean of 502 on the Critical Reading part of the test?
b. What is the probability a random sample of 90 test takers will provide a sample mean test score within 10 points of the population mean of 515 on the Mathematics part of the test (to 4 decimals)?
c. What is the probability a random sample of 100 test takers will provide a sample mean test score within 10 of the population mean of 494 on the writing part of the test (to 4 decimals)?