6. A market research firm conducts telephone surveys with a 40% historical response rate. What is the probability that in a new sample of 400 telephone numbers, at least 150 individuals will cooperate and respond to the questions? In other words, what is the probability that the sample proportion will be at least 150/400 = .375 (to 4 decimal)? Use z-table.

7.People end up tossing 12% of what they buy at the grocery store (Reader's Digest, March 2009). Assume this is the true population proportion and that you plan to take a sample survey of 540 grocery shoppers to further investigate their behavior. Use z-table.

1. Show the sampling distribution of (), the proportion of groceries thrown out by your sample respondents (to 4 decimals). SelectCannot assumed to be normally distributedCan assume to be normally distributed because n>=30 and sigma is givenCan assume to be normally distributed because n>100Can assume to be normally distributed because the underlying population is normally distributed and sigma is givenCan assume to be normally distributed because np>=5 and n(1-p)>=5Item 1 p = standard error of the proportion () =
2. What is the probability that your survey will provide a sample proportion within .03 of the population proportion (to 4 decimals)?
3. What is the probability that your survey will provide a sample proportion within .015 of the population proportion (to 4 decimals)?

8.he 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 = 100.

1. What is the probability a 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 (to 4 decimals)? Round z value in intermediate calculation to 2 decimals places.
2. What is the probability a 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)? Round z value in intermediate calculation to 2 decimals places.
3. What is the probability a sample of 100 test takers will provide a sample mean test score within 10 points of the population mean of 494 on the writing part of the test (to 4 decimals)? Round z value in intermediate calculation to 2 decimals places.