Learning Materials
Features
Discover
Chapter 11: Q. 11.33 (page 460)
Obtain a sample size that will ensure a margin of error of at most the one specified.
Margin of error
Confidence level
The required sample size is
Over 30 million students worldwide already upgrade their learning with 91影视!
All the tools & learning materials you need for study success - in one app.
Get started for free
11.97 Sunscreen Use. Industry Research polled teenagers on sunscreen use. The survey revealed that of teenage girls and of teenage boys regularly use sunscreen before going out in the sun.
a. Identify the specified attribute.
b. Identify the two populations.
c. Are the proportions and sample proportions or population proportions? Explain your answer.
Racial Crossover. In the paper "The Racial Crossover in Comorbidity, Disability, and Mortality" (Demography, Vol. 37(3), pp. 267-283), N. Johnson investigated the health of independent random samples of white and African-American elderly (aged 70 years or older). Of the 4989 white elderly surveyed, 529 had at least one stroke, whereas 103 of the 906 African-American elderly surveyed - Lported at least one stroke. At the significance level, do the data suggest that there is a difference in stroke incidence between white and African-American elderly?
Margin of error
Confidence level
Educated guess
(a) Obtain a sample size that will ensure a margin of error of at most the one specified (provided of course that the observed value of the sample proportion is further from that of the educated guess.
(b). Compare your answer to the corresponding one and explain the reason for the difference, if any.
The Nipah Virus. During one year, Malaysia was the site of an encephalitis outbreak caused by the Nipah virus, a paramyxovirus that appears to spread from pigs to workers on pig farms. As reported y K. Goh et al. in the paper "Clinical Features of Nipah Virus 臇ncephalitis among Pig Farmers in Malaysia" (New England Journal of Medicine, Vol. 342, No. 17, pp. 1229-1235), neurologists from the University of Malaysia found that, among patients infected with the Nipah virus, died from encephalitis. Find and interpret a confidence interval for the percentage of Malaysians infected with the Nipah virus who would die from encephalitis.
In discussing the sample size required for obtaining a confidence interval with a prescribed confidence level and margin of error, we made the following statement: "... we should be aware that, if the observed value of is closer to than is our educated guess, the margin of error will be larger than desired." Explain why.
One-Proportion Plus-Four z-Interval Procedure. To obtain a plus four -interval for a population proportion, we first add two successes and two failures to our data (hence, the term "plus four") and then apply Procedure on page to the new data. In other words, in place of (which is ), we use . Consequently, for a confidence level of , the endpoints of the plus-four -interval are
As a rule of thumb, the one-proportion plus-four -interval procedure should be used only with confidence levels of or greater and sample sizes of or more.
What do you think about this solution?
We value your feedback to improve our textbook solutions.
Explanations 
Textbooks 
Flashcards 
91影视 AI 
Notes 
Study Plans 
Study Sets 
Find a degree 
Magazine