1

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A sample that does not provide a good representation of the population from which it was collected is referred to as a(n)____________sample.

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A. BiasedB. EmpiricalC. StatisticsD. Inferential

Question2

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The standard deviation of the sampling distribution of the sample mean is equal to,the standard deviation of the population.

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TrueFalse

Question3

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Sales prices of baseball cards from the 1960's are known to possess a skewed-right distribution with a mean sale price of $5.25 and a standard deviation of $2.80. Suppose a random sample of 100 cards from the 1960's is selected. Describe the sampling distribution for the sample mean sale price of the selected cards.

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A. Skewed-right with a mean of $5.25 and a standard error of $2.80B. Normal with a mean of $5.25 and a standard error of $0.28C. Skewed-right with a mean of $5.25 and a standard error of $0.28D. Normal with a mean of $5.25 and a standard error of $2.80

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In a local university,40% of the students live in the dormitories. A random sample of 80 students is selected for a particular study. What is the probability that the sample proportion (the proportion living in the dormitories) is between 0.30 and 0.50?

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A. 0.9328B. 0.9664C. 0.0672D. 0.0336

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If a statistic tends to assume values higher than the population parameter as frequently as it tends to assume values that are lower, we say that the statistic is an unbiased estimate of the parameter.

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TrueFalse

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At a computer manufacturing company, the actual size of computer chips is normally distributed with a mean of 1 centimeter and a standard deviation of 0.1 centimeter. A random sample of 12 computer chips is taken. Above what value do 2.5% of the sample means fall?

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A. 1.1960B. 1.0566C. 0.8040D. 0.9434

Question7

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The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed, with mean of 3.2 pounds and standard deviation of 0.8 pound. If a sample of 64 fish yields a mean of 3.4 pounds, what is probability of obtaining a sample mean this large or larger?

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A. 0.0013B. 0.9772C. 0.0228D. 0.4772

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There are 500 employees in a firm; 45% are union members. A sample of 60 employees is selected randomly. What is the value for the standard error of proportion

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A. 0.0642B. 0.9390C. 0.0603D. 0.7939

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Assume that 14% of the items produced in an assembly line operation are defective, but that the firms production manager is not aware of this situation. Assume further that the quality assurance department to determine the quality of the assembly operation tests 50 parts. What is the probability that the sample will contain at least 5 defective items?

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A. 0.4484B. 0.5C. 0.2061D. 0.7935

Question10

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The amount of bleach a machine pours into bottles has a mean of 36 oz. with a standard deviation of 0.15 oz. Suppose we take a random sample of 36 bottles filled by this machine. The probability that the mean of the sample is between 35.95 and 35.98 oz. is equal to

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A. 0.9772B. 0.1891C. 0.8109D. 0.7881

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The standard error of the mean

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A. Is never larger than the standard deviation of the population.B. Decreases as the sample size increases.C. Measures the variability of the mean from sample to sample.D. All of the above

Question12

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A local bank reported to the federal government that its 5,246 saving accounts have a mean of $1,000 and standard deviation of $240. Government auditors have asked to randomly sample 64 of the bank's accounts to assess the reliability of the mean balance reported by the bank. If the bank information is correct, What is the probability that the sample mean balance would be less than $928?

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A. 0.1179B. 0.8821C. 0.0082D. 0.9918

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The Central Limit Theorem states that the sampling distribution of the sample mean is approximately normal whenever the population from which we are sampling is normally distributed.

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TrueFalse

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Major league baseball salaries averaged $1.5 million with a standard deviation of $0.8 million in 1994. Suppose a sample of 100 major league players was taken. Find the approximate probability that the average salary of the 100 players exceeded $1 million.

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A. 0.2357B. Approximately 0C. Approximately 1D. 0.7357

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An automobile repair shop has determined that the average service time on an automobile is 2 hours with a standard deviation of 32 minutes. A random sample of 64 out of 400 services is selected. What is the probability that this sample will have a mean service time greater than 114 minutes?

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A. 0.9484B. 0.9332C. 0.0668D. 0.0516