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StatisticsEssentials of Statistics for the Behavioral SciencesStandardized measures seem to indicate that the average level of anxiety has increased gradually over the past 50 years (Twenge, 2000). In the 1950s, the average score on the Child Manifest Anxiety Scale was μ = 15.1. A sample of n = 16 of today’s children produces a mean score of M = 23.3 with SS – 240. a. Based on the sample, has there been a significant change in the average level of anxiety since the 1950s? Use a two-tailed test with α = .01. b. Make a 90% confidence interval estimate of today’s population mean level of anxiety. c. Write a sentence that demonstrates how the outcome of the hypothesis test and the confidence interval would appear in a research report.BuyFind*arrow_forward*

8th Edition

Frederick J Gravetter + 1 other

Publisher: Cengage Learning

ISBN: 9781133956570

Chapter 9, Problem 13P

Textbook Problem

Standardized measures seem to indicate that the average level of anxiety has increased gradually over the past 50 years (Twenge, 2000). In the 1950s, the average score on the Child Manifest Anxiety Scale was μ = 15.1. A sample of *n* = 16 of today’s children produces a mean score of *M* = 23.3 with *SS* – 240.

**a.** Based on the sample, has there been a significant change in the average level of anxiety since the 1950s? Use a two-tailed test with α = .01.

**b.** Make a 90% confidence interval estimate of today’s population mean level of anxiety.

**c.** Write a sentence that demonstrates how the outcome of the hypothesis test and the confidence interval would appear in a research report.

Essentials of Statistics for the Behavioral Sciences

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Ch. 9.1 - Under what circumstances is a t statistic used...Ch. 9.1 - A sample of n = 9 scores has SS = 288. a. Compute...Ch. 9.1 - In general, a distribution of t statistics is...Ch. 9.1 - A researcher reports a t statistic with df = 20....Ch. 9.1 - For df = 15, find the value(s) of t associated...Ch. 9.2 - A sample of n = 4 individuals is selected from a...Ch. 9.3 - If all other factors are held constant, an 80%...Ch. 9.3 - If all other factors are held constant, a...Ch. 9.3 - A sample of n = 16 individuals is selected from a...Ch. 9.3 - How does sample size influence the outcome of a...

Ch. 9.4 - A new over-the-counter cold medication includes a...Ch. 9 - Under what circumstances is a t statistic used...Ch. 9 - A sample of n = 25 scores has a mean of M = 83 and...Ch. 9 - Find the estimated standard error for the sample...Ch. 9 - Explain why t distributions tend to be flatter and...Ch. 9 - Find the t values that form the boundaries of the...Ch. 9 - The following sample of n = 6 scores was obtained...Ch. 9 - The following sample was obtained from a...Ch. 9 - A random rumple of n = 25 individuals is selected...Ch. 9 - To evaluate the effect of a treatment, a sample is...Ch. 9 - To evaluate the effect of a treatment, a sample of...Ch. 9 - The spotlight effect refers to overestimating the...Ch. 9 - Many animals, including humans, tend to avoid...Ch. 9 - Standardized measures seem to indicate that the...Ch. 9 - The librarian at the local elementary school...Ch. 9 - For several years researchers have noticed that...Ch. 9 - Weinstein, McDermott, and Roediger (2010) report...Ch. 9 - Ackerman and Goldsmith (2011) found that students...Ch. 9 - A random sample of n = 16 scores is obtained from...Ch. 9 - A random sample is obtained from a population with...Ch. 9 - An example of the vertical-horizontal illusion is...Ch. 9 - McGee and Shevlin (2009) demonstrated that an...Ch. 9 - Oishi and Shigehiro (2010) report that people who...Ch. 9 - Research examining the effects of pie school child...

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