Determining
32. Chickenpox You plan to conduct a survey to estimate the percentage of adults who have had chickenpox. Find the number of people who must be surveyed if you want to be 90% confident that the sample percentage is within two percentage points of the true percentage for the population of all adults.
a. Assume that nothing is known about the prevalence of chickenpox.
b. Assume that about 95% of adults have had chickenpox.
c. Does the added knowledge in part (b) have much of an effect on the sample size?
Want to see the full answer?
Check out a sample textbook solutionChapter 7 Solutions
Essentials of Statistics, Loose-Leaf Edition PLUS MyLab Statistics with Pearson eText -- Access Card Package (6th Edition)
- AP1.2 A child is 40 inches tall, which places her at the 90th percentile of all children of similar age. The heights for children of this age form an approximately Normal distribution with a mean of 38 inches. Based on this information, what is the standard deviation of the heights of all children of this age? 0.20 inches (c) 0.65 inches (e) 1.56 inches 0.31 inches (d) 1.21 inchesarrow_forwardAP1.1 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_forward
- Please could you explain why 0.5 was added to each upper limpit of the intervals.Thanksarrow_forward28. (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_forward
- Holt Mcdougal Larson Pre-algebra: Student Edition...AlgebraISBN:9780547587776Author:HOLT MCDOUGALPublisher:HOLT MCDOUGALGlencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill
- Big Ideas Math A Bridge To Success Algebra 1: Stu...AlgebraISBN:9781680331141Author:HOUGHTON MIFFLIN HARCOURTPublisher:Houghton Mifflin Harcourt