Chapter 9: Q. 1 (page 563)
Mr. Tabor believes that less than of the students at his school completed their math homework last night. The math teachers inspect the homework assignments from a random sample of students at the school.
Chapter 9: Q. 1 (page 563)
Mr. Tabor believes that less than of the students at his school completed their math homework last night. The math teachers inspect the homework assignments from a random sample of students at the school.
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Get started for freeFast connection? How long does it take for a chunk of information to travel
from one server to another and back on the Internet? According to the site
internettrafficreport.com, the average response time is 200 milliseconds (about one-fifth of a second). Researchers wonder if this claim is true, so they collect data on response times (in milliseconds) for a random sample of 14 servers in Europe. A graph of the data reveals no strong skewness or outliers.
a. State an appropriate pair of hypotheses for a significance test in this setting. Be sure to define the parameter of interest.
b. Check conditions for performing the test in part (a).
c. The 95% confidence interval for the mean response time is 158.22 to 189.64
milliseconds. Based on this interval, what conclusion would you make for a test of the hypotheses in part (a) at the 5% significance level?
d. Do we have convincing evidence that the mean response time of servers in the United States is different from 200 milliseconds? Justify your answer.
Pressing pills A drug manufacturer forms tablets by compressing a granular material that contains the active ingredient and various fillers. The hardness of a sample from each batch of tablets produced is measured to control the compression process. The target value for the hardness is The hardness data for a random sample of 20 tablets from one large batch are
Is there convincing evidence at the level that the mean hardness of the tablets in this batch differs from the target value?
You are testing against based on an SRS of
observations from a Normal population. What values of the t statistic are statistically significant at the level?
Do you Tweet? The Pew Internet and American Life Project asked a random sample of U.S. adults, โDo you ever โฆ use Twitter or another service to share updates about yourself or to see updates about others?โ According to Pew, the resulting 95% confidence interval is (0.123, 0.177).11 Based on the confidence interval, is there convincing evidence that the true proportion of U.S. adults who would say they use Twitter or another service to share updates differs from 0.17? Explain your reasoning.
Which of the following has the greatest probability?
a.if t has 5 degrees of freedom.
b. if t has 2 degrees of freedom.
c. if z is a standard Normal random variable.
d.if t has 5 degrees of freedom.
e. if z is a standard Normal random variable.
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