12th Edition

ISBN: 9780321836960

Author: Mario F. Triola

Publisher: PEARSON

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 9.5, Problem 7BSC

Hypothesis Tests of Claims About Variation. In Exercises 7–16, test the given claim. Assume that both samples are independent simple random samples from populations having normal distributions.

7. Color and Cognition Example 1 in this section included results from a study of the effects of color on creativity, and the results below were used to study the effects of color on cognition. Words were displayed on a computer screen with background colors of red and blue. Results from scores on a test of word recall arc given below. Use a 0.05 significance level to test the claim that the samples arc from populations with the same standard deviation. Does the background color appear to have an effect on the variation of word recall scores?

Red Background: n = 35 , x ¯ = 15.89 , s = 5.90 Blue Background: n = 36 , x ¯ = 12.31 , s = 5.48

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 9.5, Problem 6BSC

Chapter 9.5, Problem 8BSC

Chapter 9 Solutions

Elementary Statistics

Ch. 9.2 - Verifying Requirements In the largest clinical...Ch. 9.2 - Verifying Requirements In the largest clinical...Ch. 9.2 - Hypotheses and Conclusions Refer to the hypothesis...Ch. 9.2 - Using Confidence Intervals a. Assume that we want...Ch. 9.2 - Interpreting Displays. In Exercises 5 and 6, use...Ch. 9.2 - Interpreting Displays. In Exercises 5 and 6, use...Ch. 9.2 - Testing Claims About Proportions. In Exercises...Ch. 9.2 - Prob. 8BSC Ch. 9.2 - Testing Claims About Proportions. In Exercises...Ch. 9.2 - Testing Claims About Proportions. In Exercises...

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Solution Summary: The author concludes that there is no sufficient evidence to support the claim that the samples are from populations with the same standard deviation.

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