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 free7.47 Baby Weight. The paper "Are Babies Normal?" by T. Clemons and M. Pagano (The American Statistician, Vol. 53, No, 4. pp. 298-302) focused on birth weights of babies. According to the article, the mean birth weight is grams ( pounds, ounces) with a standard deviation of 581 grams.
a. Identify the population and variable.
b. For samples of size , find the mean and standard deviation of all possible sample mean weights.
c. Repeat part (b) for samples of size.
A variable of a population has a mean of and a standard deviation of
a. If the variable is normally distributed, identify the sampling distribution of the sample mean for samples of size
b. Can you answer part (a) if the distribution of the variable under consideration is unknown? Explain your answer.
c. Can you answer part (a) if the distribution of the variable under consideration is unknown but the sample size is instead of ?
Why or why not?
7.49 Mobile Homes. According to the U.S. Census Bureau publication Manufactured Housing Statistics, the mean price of new mobile homes is . Assume a standard deviation of . Let denote the mean price of a sample of new mobile homes.
a. For samples of size , find the mean and standard deviation of . Interpret your results in words.
b. Repeat part (a) with .
In Example 7.5, we used the definition of the standard deviation of a variable to obtain the standard deviation of the heights of the five starting players on a men's basketball team and also the standard deviation of for samples of sizes 1,2,3,4,5.The results are summarized in Table 7.6on page 298. Because the sampling is without replacement from a finite population, Equation (7.1) can also be used to obtain .
Part (a): Apply Equation (7.1) to compute for sample sizes of 1,2,3,4,5. Compare your answers with those in Table 7.6.
Part (b): Use the simpler formula, Equation (7.2) to compute for samples of sizes 1,2,3,4,5.Compare your answers with those in Table 7.6. Why does Equation (7.2)generally yield such poor approximations to the true values?
Part (c): What percentages of the population size are samples of sizes 1,2,3,4,5.
A variable of a population is normally distributed with mean and standard deviation . For samples of size , fill in the blanks. Justify your answers.
a. Approximately of all possible samples have means that lie within of the population mean,
b. Approximately of all possible samples have means that lie within of the population mean,
c. Approximately of all possible samples have means that lie within of the population mean,
d. of all possible samples have means that lie within of the population mean, (Hint: Draw a graph for the distribution of , and determine the scores dividing the area under the normal curve into a middle area and two outside areas of
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