Chapter 8: Q. T8.2 (page 549)
The weights (in pounds) of three adult males are,and. What is the standard error of the mean for these data?
a.
b.
c.
d.
e.
Short Answer
The standard error of the mean is
Chapter 8: Q. T8.2 (page 549)
The weights (in pounds) of three adult males are,and. What is the standard error of the mean for these data?
a.
b.
c.
d.
e.
The standard error of the mean is
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Get started for freeCheck them all Determine if the conditions are met for constructing a confidence interval for the population mean in each of the following settings.
a. We want to estimate the average age at which U.S. presidents have died. So we obtain a list of all U.S. presidents who have died and their ages at death.
b. 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 boxplot displays the difference (Texts − Calls) for each student.
Critical values What critical value from Table B should be used for a
confidence interval for the population mean in each of the following situations?
a. A confidence interval based on randomly selected observations
b. confidence interval from an SRS of observations
c. A confidence interval based on a random sample of individuals
Suppose we want a 90% confidence interval for the average amount spent on books by freshmen in their first year at a major university. The interval is to have a margin of error of \(2. Based on last year’s book sales, we estimate that the standard deviation of the amount spent will be close to \)30. The number of observations required is closest to
(a) 25. (b) 30. (c) 608. (d) 609. (e) 865.
A newspaper reporter asked an SRS of residents in a large city for their opinion about the mayor’s job performance. Using the results from the sample, the confidence interval for the proportion of all residents in the city who approve of the mayor’s job performance is . What is the value of ?
a.
b.
c.
d.
e.
Lying online Many teens have posted profiles on sites such as Facebook. A sample survey asked random samples of teens with online profiles if they included false information in their profiles. Of younger teens (ages role="math" localid="1654194610029" ) polled, said “Yes.” Of older teens (ages ) polled, said “Yes.” A confidence interval for the true difference in the proportions of younger teens and older teens who include false information in their profile is to .
a. Interpret the confidence interval.
b. Does the confidence interval give convincing evidence of a difference in the true
proportions of younger and older teens who include false information in their profiles?
Explain your answer.
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