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.

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.

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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Confidence Intervals

When we calculate intervals in probability and statistics, it can be simply termed as finding out a confidence interval. The confidence interval is usually calculated from the data set which is observed. The value of the parameter that needs to be calculated is present here only.

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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.

Definition Definition Method in statistics by which an observation’s uncertainty can be quantified. The main use of interval estimating is for describing a range that is made by transforming a point estimate by determining the range of values, or interval within which the population parameter is likely to fall. This range helps in measuring its precision.

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