How much does the fat content of Brand hot dogs vary? To find out, researchers measured the fat content (in grams) of a random sample of Brand X hot dogs. A confidence interval for the population standard deviation is to .
1. Interpret the confidence interval.
There is surety that the population standard deviation of fat content of hot dogs of brand will be lying between to .
Confidence interval .
Number of dogs .
Confidence level .
There is surety that the population standard deviation of fat content of hot dogs of brand will be lying between to
In each of the following situations, discuss whether it would be appropriate to construct a one-sample interval to estimate the population mean.
(a) We collect data from a random sample of adult residents in a state. Our goal is to estimate the overall percentage of adults in the state who are college graduates.
(b) The coach of a college men’s basketball team records the resting heart rates of the team members. We use these data to construct a confidence interval for the mean resting heart rate of all male students at this college.
(c) Do teens text more than they call? To find out, an AP Statistics class at a large high school collected data on the number of text messages and calls sent or received by each of randomly selected students. The Fathom boxplot below displays the difference (texts calls) for each student.
Election polling Gloria Chavez and Ronald Flynn are the candidates for mayor in a large city. We want to estimate the proportion of all registered voters in the city who plan to vote for Chavez with % conﬁdence and a margin of error no greater than . How large a random sample do we need? Show your work.
A researcher plans to use a random sample of families to estimate the mean monthly family income for a large population. A confidence interval based on the sample would be ______ than a 90% confidence interval.
(a) narrower and would involve a larger risk of being incorrect
(b) wider and would involve a smaller risk of being incorrect
(c) narrower and would involve a smaller risk of being incorrect
(d) wider and would involve a larger risk of being incorrect
(e) wider, but it cannot be determined whether the risk of being incorrect would be larger or smaller
An online poll posed the following question:
It is now possible for school students to log on to Internet sites and download homework. Everything from book reports to doctoral dissertations can be downloaded free or for a fee. Do you believe that giving a student who is caught plagiarizing an F for their assignment is the right punishment?
Of the people who responded, clicked “Yes.” That’s of the sample. Based on this sample, a confidence interval for the percent of the population who would say “Yes” is . Which of the three inference conditions is violated? Why is this confidence interval worthless?
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