8th Edition

ISBN: 9781305104174

Author: David B. Johnson, Thomas A. Mowry

Publisher: Cengage Learning

Concept explainers

The method used for finding the corresponding z-critical value in a normal distribution using the known probability is said to be an inverse normal distribution. The inverse normal distribution is a continuous probability distribution with a family of tw…

Mean, Median, Mode

It is a descriptive summary of a data set. It can be defined by using some of the measures. The central tendencies do not provide information regarding individual data from the dataset. However, they give a summary of the data set. The central tendency o…

Z-Scores

A z-score is a unit of measurement used in statistics to describe the position of a raw score in terms of its distance from the mean, measured with reference to standard deviation from the mean. Z-scores are useful in statistics because they allow compar…

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Textbook Question

Chapter 4.4, Problem 16E

A population X is normally distributed with mean 72.1 and standard deviation 9.3 . For each of the following values of x, find the corresponding z-number. Round off your answers to two decimal places.
a.	x = 90	b.	x = 80
c.	x = 75	d.	x = 70
e.	x = 60	f.	x = 50

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 4.4, Problem 15E

Chapter 4.4, Problem 17E

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Chapter 4 Solutions

Mathematics: A Practical Odyssey

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A population X is normally distributed with mean 72.1 and standard deviation 9.3 . For each of the following values of x , find the corresponding z -number. Round off your answers to two decimal places. a. x = 90 b. x = 80 c. x = 75 d. x = 70 e. x = 60 f. x = 50

Solution Summary: The author calculates the z number by subtracting 90, 72.1, and 9.3 in the above-mentioned formula.

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