Learning Materials
Features
Discover
Chapter 8: Q.3.1 (page 511)
Define the parameter of interest.
Parameter of interest is the variable on which whole focal point of the scientist lies. Here, rate of healing wounds is being estimated by the biologists. In this way, one might say that the mean healing rate of wounds is the parameter of interest.
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
A radio talk show host with a large audience is interested in the proportion of adults in his listening area who think the drinking age should be lowered to eighteen. To find this out, he poses the following question to his listeners: "Do you think that the drinking age should be reduced to eighteen in light of the fact that eighteen-year-olds are eligible for military service?" He asks listeners to phone in and vote "Yes" if they agree the drinking age should be lowered and "No" if not. Of the people who phoned in, answered "Yes." Which of the following conditions for inference about a proportion using a confidence interval are violated?
I. The data are a random sample from the population of interest.
II. is so large that both are at least .
III. The population is at least times as large as the sample.
(a) I only
(c) III only
(c) I, II, and III
(b) II only
(d) I and II only
Teens' online profiles Over half of all American teens (ages 12 to 17 years) have an online profile, mainly on Facebook. A random sample of 487 teens with profiles found that 385 included photos of themselves.
(a) Construct and interpret a confidence interval for . Follow the four-step process.
(b) Is it plausible that the true proportion of American teens with profiles who have posted photos of themselves is Use your result from part (a) to support your answer.
Running red lights A random digit dialing telephone survey ofdrivers asked, "Recalling the last ten traffic lights you drove through, how many of them were red when you entered the intersections?" Of the respondents, admitted that at least one light had been red.
(a) Construct and interpret aconfidence interval for the population proportion.
(b) Nonresponse is a practical problem for this survey-only of calls that reached a live person were completed. Another practical problem is that people may not give truthful answers. What is the likely direction of the bias: do you think more or fewer than of the respondents really ran a red light? Why? Are these sources of bias included in the margin of error?
How many people live in South African households? To find out, we collected data from an SRS of 48 out of the over 700,000 South African students who took part in
the CensusAtSchool survey project. The mean number of people living in a household was 6.208; the standard deviation was 2.576.
(a) Is the Normal condition met in this case? Justify your answer.
(b) Maurice claims that a 95% confidence interval for the population mean is . Explain why this interval is wrong. Then give the correct interval.
School vouchers A national opinion poll found that % of all American adults agree that parents should be given vouchers that are good for education at any public or private school of their choice. The result was based on a small sample.
(a) How large an SRS is required to obtain a margin of error of (that is, ) in a % con铿乨ence interval? Answer this question using the previous poll鈥檚 result as the guessed value for .
(b) Answer the question in part (a) again, but this time use the conservative guess . By how much do the two sample sizes differ?
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