Chapter 7: Q.2.2 (page 420)
Imagine taking an SRS of . Make a graph showing a possible distribution of the sample data. Give the value of the appropriate statistic for this sample.
Short Answer
The test statistic is .
Chapter 7: Q.2.2 (page 420)
Imagine taking an SRS of . Make a graph showing a possible distribution of the sample data. Give the value of the appropriate statistic for this sample.
The test statistic is .
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Get started for freeWhen people order books from a popular online source, they are shipped in standard-sized boxes. Suppose that the mean weight of the boxes ispounds with a standard deviation of pounds, the mean weight of the packing material is pounds with a standard deviation of 0.1 pounds, and the mean weight of the books shipped is pounds with a
standard deviation of pounds. Assuming that the weights are independent, what is the standard deviation of the total weight of the boxes that are shipped from this source?
(a)
(b)
(c)
(d)
(e)
Predict the election Just before a presidential election, a national opinion poll increases the size of its weekly random sample from the usual people to people.
(a) Does the larger random sample reduce the bias of the poll result? Explain.
(b) Does it reduce the variability of the result? Explain
Scrabble In the game of Scrabble, each player begins by drawing 7 tiles from a bag containing 100 tiles. There are 42 vowels, 56 consonants, and 2 blank tiles in the bag. Cait chooses an SRS of 7 tiles. Let be the proportion of vowels in her sample.
(a) Is the condition met in this case? Justify your answer.
(b) Is the Normal condition met in this case? Justify your answer.
Thousands of travelers pass through the airport in Guadalajara, Mexico, each day. Before leaving the airport, each passenger must pass through the Customs inspection area. Customs agents want to be sure that passengers do not bring illegal items into the country. But they do not have time to search every traveler’s luggage. Instead, they require each person to press a button. Either a red or a green bulb lights up. If the red light shows, the passenger will be searched by Customs agents. A green light means “go ahead.” Customs agents claim that the proportion of all travelers who will be stopped (red light) is, because the light has probability of showing red on any push of the button. To test this claim, a concerned citizen watches a random sample of travelers push the button. Only get a red light.
(a) Assume that the Customs agents’ claim is true. Find the probability that the proportion of travelers who get a red light is as small as or smaller than the result in this sample. Show your work.
(b) Based on your results in (a), do you believe the Customs agents’ claim? Explain.
A large company is interested in improving the efficiency of its customer service and decides to examine the length of the business phone calls made to clients by its sales staff. A cumulative relative frequency graph is shown below from data collected over the past year. According to the graph, the shortest of calls will take how long to complete?
(a) Less than minutes.
(b) At least minutes.
(c) Exactly minutes.
(d) At least minutes.
(e) Less than minutes.
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