An Introduction to Statistical Methods and Data Analysis

7th Edition

ISBN: 9781305269477

Author: R. Lyman Ott, Micheal T. Longnecker

Publisher: Cengage Learning

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Estimation

A new framework of data analysis where the new statistical methods are used for interpreting the results and analyzing the data is known as estimation in statistics.

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Chapter 7.7, Problem 14E

Random samples of sizes n₁ = 25 and n₂ = 20 were selected from populations A and B, respectively. From the samples, the standard deviations were computed to be s₁ = 5.2 and s₂ = 6.8.

a. Do the data provide substantial evidence to indicate the populations have different standard deviations? Use α = .05.
b. Estimate the relative sizes of the standard deviations by constructing a 95% confidence interval for the ratio of the standard deviations σ₁/σ₂.
c. The data and populations must satisfy what conditions in order for your test and confidence interval to be valid?

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 7.7, Problem 13E

Chapter 7.7, Problem 15E

Chapter 7 Solutions

An Introduction to Statistical Methods and Data Analysis

Ch. 7.7 - A leading researcher in the study of interstate...Ch. 7.7 - Baseballs vary somewhat in their rebounding...Ch. 7.7 - Random samples of sizes n1 = 25 and n2 = 20 were...Ch. 7.7 - A soft-drink firm is evaluating an investment in a...Ch. 7.7 - A wildlife biologist was interested in determining...Ch. 7.7 - Prob. 30SE

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