10th Edition

ISBN: 9780321989178

Author: Neil A. Weiss

Publisher: PEARSON

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Textbook Question

Chapter 8.2, Problem 85E

Pulmonary Hypertension. In the paper “Persistent Pulmonary Hypertension of the Neonate and Asymmetric Growth Restriction” (Obstetrics & Gynecology, Vol. 91, No. 3, pp, 336–341), M. Williams et al. reported on a study of characteristics of neonates, Infants treated for pulmonary hypertension, called the PH group, were compared with those not so treated, called the control group. One of the characteristics measured was head circumference. The mean head circumference of the 10 infants in the PH group was 34.2 centimeters (cm).

a. Assuming that head circumferences for infants treated for pulmonary hypertension are normally distributed with standard deviation 2.1 cm, determine a 90% confidence interval for the mean head circumference of all such infants.
b. Obtain the margin of error, E, for the confidence interval you found in part (a).
c. Explain the meaning of E in this context in terms of the accuracy of the estimate.
d. Determine the sample size required to have a margin of error of 0.5 cm with a 95% confidence level.

Features Features Normal distribution is characterized by two parameters, mean (µ) and standard deviation (σ). When graphed, the mean represents the center of the bell curve and the graph is perfectly symmetric about the center. The mean, median, and mode are all equal for a normal distribution. The standard deviation measures the data's spread from the center. The higher the standard deviation, the more the data is spread out and the flatter the bell curve looks. Variance is another commonly used measure of the spread of the distribution and is equal to the square of the standard deviation.

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Chapter 8.2, Problem 84E

Chapter 8.2, Problem 86E

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Pulmonary Hypertension. In the paper “Persistent Pulmonary Hypertension of the Neonate and Asymmetric Growth Restriction” (Obstetrics&Gynecology, Vol. 91, No. 3, pp. 336–341), M. Williams et al. reported on a study of characteristics of neonates. Infants treated for pulmonary hypertension, called the PH group, were compared with those not so treated, called the control group. One of the characteristics measured was head circumference. The mean head circumference of the 10 infants in the PH group was 34.2 centimeters (cm). a. Assuming that head circumferences for infants treated for pulmonary hypertension are normally distributed with standard deviation 2.1 cm, determine a 90% confidence interval for the mean head circumference of all such infants. b. Obtain the margin of error, E, for the confidence interval you found in part (a). c. Explain the meaning of E in this context in terms of the accuracy of the estimate. d. Determine the sample size required to have a margin of error of…

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Chapter 8 Solutions

Introductory Statistics (10th Edition)

Ch. 8.1 - The value of a statistic used to estimate a...Ch. 8.1 - What is a confidence-interval estimate of a...Ch. 8.1 - Prob. 3E Ch. 8.1 - Prob. 4E Ch. 8.1 - Prob. 5E Ch. 8.1 - Suppose that you lake 500 simple random samples...Ch. 8.1 - Prob. 7E Ch. 8.1 - A simple random sample is taken from a population...Ch. 8.1 - Refer to Exercise 8.7 and find a point estimate...Ch. 8.1 - Prob. 10E

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Solution Summary: The author analyzes the 90% confidence interval for the population mean head circumference of infants in the PH group.

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