Chapter 7: Q. 7.45 (page 301)
7.45 NBA Champs. Repeat parts (b) and (c) of Exercise for samples of size . For part (b). use your answer to Exercise .
Short Answer
The mean height for samples of size is .
Chapter 7: Q. 7.45 (page 301)
7.45 NBA Champs. Repeat parts (b) and (c) of Exercise for samples of size . For part (b). use your answer to Exercise .
The mean height for samples of size is .
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Get started for freeA variable of a population has mean μ and standard deviation. that For a large sample size n, answer the following questions.
a. Identify the distribution of
b. Does your answer to part (a) depend on n being large? Explain your answer.
c. Identify the mean and the standard deviation of
d. Does your answer to part (c) depend on the sample size being large? Why or why not?
Worker Fatigue. A study by M. Chen et al. titled "Heat Stress Evaluation and Worker Fatigue in a Steel Plant (American Industrial Hygiene Association, Vol. 64. Pp. 352-359) assessed fatigue in steelplant workers due to heat stress. If the mean post-work heart rate for casting workers equals the normal resting heart rate of beats per minute (bpm), find the probability that a random sample of casting workers will have a mean post-work heart rate exceeding Assume that the population standard deviation of post-work heart rates for casting workers is bpm. State any assumptions that you are making in solving this problem.
As reported by the U.S. Census Bureau in Educational Attainment in the United States, the percentage of adults in each state who have completed a bachelor's degree is provided on the Weiss Stats site. Use the technology of you choice to solve the following problems.
Part (a): Obtain the standard deviation of the variable "percentage of adults who have completed a bachelor's degree" for the population of 50 states.
Part (b): Consider simple random samples without replacement from the population of 50 states. Strictly speaking, which is the correct formula for obtaining the standard deviation of the sample mean- Equation (7.1) or Equation (7.2)? Explain your answer.
Part (c): Referring to part (b), obtain R for simple random samples of size 30 by using both formulas. Why does Equation (7.2) provide such a poor estimate of the true value given by Equation (7.1)?
Part (d): Referring to part (b), obtain R for simple random samples of size 2 by using both formulas. Why does Equation (7.2) provide a somewhat reasonable estimate of the true value given by Equation (7.1)?
According to the central limit theorem, for a relatively large sample size, the variable is approximately normally distributed.
a. What rule of thumb is used for deciding whether the sample size is relatively large?
b. Roughly speaking, what property of the distribution of the variable under consideration determines how large the sample size must be for a normal distribution to provide an adequate approximation to the distribution of ?
Ethanol Railroad Tariffs. An ethanol railroad tariff is a fee charged for shipments of ethanol on public railroads. The Agricultural Marketing Service publishes tariff rates for railroad-car shipments of ethanol in the Biofuel Transportation Database. Assuming that the standard deviation of such tariff rates is , determine the probability that the mean tariff rate of randomly selected railroad car shipments of ethanol will be within of the mean tariff rate of all railroad-car shipments of ethanol. Interpret your answer in terms of sampling error.
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