Davis Aircraft Co. is developing a new wing de-icer system, which it has installed on 30 commercial airliners.

Problems: Sampling and Sampling Distributions

Problem-01: Sampling and Sampling Distributions

In a sample of 25 observations from a normal distribution with mean 98.6 and standard deviation 17.2

Problem-02: Sampling and Sampling Distributions

Mary Bartel, an auditor for a large credit card company, knows that, on average, the monthly balance of any given customer is $112, and the standard deviation is $56.

Problem-03: Sampling and Sampling Distributions

In a sample of 16 observations from a normal distribution with a mean of 150 and a variance of 256, what is

Problem-04: Sampling and Sampling Distributions

In a sample of 19 observations from a normal distribution with mean 18 and standard deviation 4.8

Problem-05: Sampling and Sampling Distributions

In a normal distribution with mean 56 and standard deviation 21, how large a sample must be taken so that there will be at least a 90 percent chance that...

Problem-06: Sampling and Sampling Distributions

In a normal distribution with mean 375 and standard deviation 48, how large a sample must be taken so that the probability will be at least 0.95 that the sample...

Problem-07: Sampling and Sampling Distributions

An astronomer at the Mount Palomar Observatory notes that during the Gemind meteor shower, an average of 50 meteors appears each hour, with a variance of 9 meteors squared. The...

Problem-08: Sampling and Sampling Distributions

The average cost of a studio condominium in the Cedar Lakes development is $62,000 and the standard deviation is $4,200. What is the probability that a condominium in this development...

Problem-09: Sampling and Sampling Distributions

Robertson Employment Service customarily gives standard intelligence and aptitude tests to all people who seek employment through the firm. The firm has collected data for several years and has found...

Problem-10: Sampling and Sampling Distributions

An oil refinery has backup monitors to keep track of the refinery flows continuously and to prevent machine malfunctions from disrupting the standard deviation of 730 hours. In addition to...

Problem-11: Sampling and Sampling Distributions

A recent study by the EPA has determined that the amount of contaminants in Minnesota lakes (in parts per million) is normally distributed with mean 64 ppm and variance 17.6,...

Problem-11: Sampling and Sampling Distributions

Calvin Ensor, president of General Telephone Corp, is upset at the number of telephones produced by GTC that have faulty receivers.

Problem-11: Sampling and Sampling Distributions

Clara Voyant, Whose job is predicting the future for her venture capital company, has just received the statistics describing her company's performance on 1,800 investments last year.

Problem-14: Sampling and Sampling Distributions

Farmer Braun, Who sells grain to Germany, owns 60 acres of wheat fields. Based on past experience, he knows that the yield from each individual acre is normally distributed with...

Problem-15: Sampling and Sampling Distributions

A ferry carries 25 passengers. The weight of each passenger has a normal distribution with mean 168 pounds and variance 361 pounds squared.

Problem-16: Sampling and Sampling Distributions

From a population of 125 items with a mean of 105 and a standard deviation of 17,64 items were chosen.

Problem-17: Sampling and Sampling Distributions

Jonida Martinez, researcher for the Columbian Coffee Corporation, is interested in determining the rate of coffee usage per household in the United States.

Problem-18: Sampling and Sampling Distributions

From a population of 75 items with a mean of 364 and a variance of 18, 32 items were randomly selected without replacement.

Problem-19: Sampling and Sampling Distributions

Given a population of size N = 80 with a mean of 22 and a standard deviation of 3.2 what is the probability that a sample of 25 will have...

Problem-20: Sampling and Sampling Distributions

For a population of size N = 80 with a mean of 8.2 and a standard deviation of 2.1, find the standard error of the mean for the following sample...

Problem-21: Sampling and Sampling Distributions

Tread-On-Us has desgned a new tire, and they don't know what the average amount of tread life is going to be.

Problem-22: Sampling and Sampling Distributions

An underwater salvage team is preparing to explore a site off the coast of Florida where an entire flotilla of 45 Spanish galleons sank.

Problem-23: Sampling and Sampling Distributions

An X-ray technician is taking readings from her machine to ensure that it adheres to federal safety guidelines.

Problem-24: Sampling and Sampling Distributions

Sara Gordon is heading a fund - raising drive for Milford College. She wishes to concentrate on the current tenth-reunion class, and hopes to get contributions from 36 percent of...

Problem-25: Sampling and Sampling Distributions

Davis Aircraft Co. is developing a new wing de-icer system, which it has installed on 30 commercial airliners.

Problem-26: Sampling and Sampling Distributions

Food Place, a chain of 145 supermarkets, has been bought out by a larger nationwide supermarket chain.

Problem-27: Sampling and Sampling Distributions

Miss Joanne Happ, chief executive officer of Southwestern Life & Surety Corp, wants to undertake a survey of the huge number of insurance policies that her company has underwritten.

Problem-28: Sampling and Sampling Distributions

By reviewing sales since opening 6 months ago, a restaurant owner found that the average bill for a couople was $26, and the standard deviation was $5.65.

Problem-29: Sampling and Sampling Distributions

The U>S. Customs Agency routinely checks all passengers arriving from foreign countries as they enter the United States.

Problem-30: Sampling and Sampling Distributions

HAL Corporation manufactures large computer systems and has always prided itself on the reliability of its System 666 central processing units.

Problem-31: Sampling and Sampling Distributions

Members of the Organization for Consumer Action send more than 250 volunteers a day all over the state to increase support for a consumer protection bill that is currently before...

Problem-32: Sampling and Sampling Distributions

Jill Johnson, product manager for Southern Electric's smoke alarm, is concerned over recent complaints from consumer groups about the short life of the device.

Problem-33: Sampling and Sampling Distributions

Seventy data clerks at the Department of Motor Vehicles make an average of 18 errors per day, normally distributed with a standard deviation of 4.

Sampling and Sampling Distributions

Problem-25: Sampling and Sampling Distributions

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