Learning Materials
Features
Discover
Chapter 9: Q 83. (page 608)
Tests and confidence intervals The value for a two-sided test of the null hypothesis is
a. Does the confidence interval for 渭 include ? Why or why not?
b. Does the confidence interval for 渭 include ? Why or why not?
Part (a) Yes.
Part (b) No.
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
Watching grass grow The germination rate of seeds is defined as the proportion of seeds that sprout and grow when properly planted and watered. A certain variety of grass seed usually has a germination rate of . A company wants to see if spraying the seeds with a chemical that is known to increase germination rates in other species will increase the germination rate of this variety of grass. The company researchers spray a random sample of grass seeds with the chemical, and of the seeds germinate. Do these data provide convincing evidence at the significance level that the chemical is
effective for this variety of grass?
Losing weight A Gallup poll found that 59% of the people in its sample said 鈥淵es鈥� when asked, 鈥淲ould you like to lose weight?鈥� Gallup announced: 鈥淔or results based on the total sample of national adults, one can say with 95% confidence that the margin of (sampling) error is 卤3 percentage points.鈥�12 Based on the confidence interval, is there convincing evidence that the true proportion of U.S. adults who would say they want to lose weight differs from 0.55? Explain your reasoning
Candy! A machine is supposed to fill bags with an average of 19.2 ounces of candy. The manager of the candy factory wants to be sure that the machine does not consistently underfill or overfill the bags. So the manager plans to conduct a significance test at the significance level of
where the true mean amount of candy (in ounces) that the machine put in all bags filled that day. The manager takes a random sample of 75 bags of candy produced that day and weighs each bag. Check if the conditions for performing the test are met.
Reality TVTelevision networks rely heavily on ratings of TV shows when deciding
whether to renew a show for another season. Suppose a network has decided that
鈥淢iniature Golf with the Stars鈥� will only be renewed if it can be established that more than of U.S. adults watch the show. A polling company asks a random sample of U.S. adults if they watch 鈥淢iniature Golf with the Stars.鈥� The network uses the data to perform a test of
where is the true proportion of all U.S. adults who watch the show. Describe a Type error and a Typeerror in this setting, and give a possible consequence of each.
Packaging DVDs A manufacturer of digital video discs (DVDs) wants to be sure that the DVDs will fit inside the plastic cases used as packaging. Both the cases and the DVDs are circular. According to the supplier, the diameters of the plastic cases vary Normally with mean inches and standard deviation inch. The DVD manufacturer produces DVDs with mean diameterinches. Their diameters follow a Normal distribution with inch.
a. Let X = the diameter of a randomly selected case and Y = the diameter of a randomly selected DVD. Describe the shape, center, and variability of the distribution of the random variable X鈭扽. What is the importance of this random variable to the DVD manufacturer?
b. Calculate the probability that a randomly selected DVD will fit inside a randomly selected case.
c. The production process runs in batches of 100 DVDs. If each of these DVDs is paired with a randomly chosen plastic case, find the probability that all the DVDs fit in their cases.
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