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Chapter 7: Q. 1.3 (page 448)
The length of human pregnancies from conception to birth varies according to a distribution that is approximately Normal with mean days and standard deviation days.
Compute the standard deviation of the sampling distribution of. Check that the condition is met.
The standard deviation is .
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Do you drink cereal milk? What sample size would be required to reduce the standard deviation of the sampling distribution to one-half the value you found in Exercise 35(b)? Justify your answer.
Airport security The Transportation Security Administration (TSA) is responsible for airport safety. On some flights, TSA officers randomly select passengers for an extra security check before boarding. One such flight had 76 passengers -12 in first class and 64 in coach class. TSA officers selected an SRS of 10 passengers for screening. Let be the proportion of first-class passengers in the sample.
(a) Is the condition met in this case? Justify your answer.
(b) Is the Normal condition met in this case? Justify your answer.
Bad carpet The number of flaws per square yard is a type of carpet material that varies with mean flaws per square yard and standard deviation flaws per square yard. The population distribution cannot be Normal, because a count takes only whole-number values. An inspector studies square yards of the material records the number of flaws found in each square yard, and calculates , the mean number of flaws per square yard inspected. Find the probability that the mean number of flaws exceeds per square yard. Follow the four-step process.
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.
About of young adult lnternet users watch online viden. Suppose that a sample survey contacts an SRS of young adult Internet users and calculates the proportion of in this sample who watch online video.
What is the mean of sampling distribution of explain
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