Concept explainers
a. If you want to estimate the percentage of adults who have a paid subscription to a printed newspaper, how many adults must you survey if you want 95% confidence that your percentage has a margin of error of three percentage points?
b. If you want to estimate the mean amount that adults have spent on printed newspapers within the past year, how many adults must you survey if you want 95% confidence that your sample mean is in error by no more than $5? (Based on results from a pilot study, assume that the standard deviation of amounts spent on printed newspapers in the last year is $47.)
c. If you plan to obtain the estimates described in parts (a) and (b) with a single survey having several questions, how many adults must be surveyed?
Want to see the full answer?
Check out a sample textbook solutionChapter 7 Solutions
ELEMENTARY STATISTICS-MYLAB STAT.ACCESS
- AP1.1 You look at real estate ads for houses in Sarasota, Florida. Many houses range from $200,000 to $400,000 in price. The few houses on the water, however, have prices up to $15 million. Which of the following statements best describes the distribution of home prices in Sarasota? The distribution is most likely skewed to the left, and the mean is greater than the median. The distribution is most likely skewed to the left, and the mean is less than the median. The distribution is roughly symmetric with a few high outliers, and the mean is approximately equal to the median. The distribution is most likely skewed to the right, and the mean is greater than the median. The distribution is most likely skewed to the right, and the mean is less than the median.arrow_forwardDuring busy political seasons, many opinion polls are conducted. In apresidential race, how do you think the participants in polls are generally selected?Discuss any issues regarding simple random, stratified, systematic, cluster, andconvenience sampling in these polls. What about other types of polls, besides political?arrow_forwardPlease could you explain why 0.5 was added to each upper limpit of the intervals.Thanksarrow_forward
- 28. (a) Under what conditions do we say that two random variables X and Y are independent? (b) Demonstrate that if X and Y are independent, then it follows that E(XY) = E(X)E(Y); (e) Show by a counter example that the converse of (ii) is not necessarily true.arrow_forward1. Let X and Y be random variables and suppose that A = F. Prove that Z XI(A)+YI(A) is a random variable.arrow_forward30. (a) What is meant by the term "product measur"? ANDarrow_forward
- Holt Mcdougal Larson Pre-algebra: Student Edition...AlgebraISBN:9780547587776Author:HOLT MCDOUGALPublisher:HOLT MCDOUGALBig Ideas Math A Bridge To Success Algebra 1: Stu...AlgebraISBN:9781680331141Author:HOUGHTON MIFFLIN HARCOURTPublisher:Houghton Mifflin Harcourt
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill