Essentials of Statistics (5th Edition)

Published by Pearson
ISBN 10: 0-32192-459-2
ISBN 13: 978-0-32192-459-9

Chapter 7 - Estimates and Sample Sizes - Review - Review Exercises - Page 367: 4

Answer

a) t-distribution b) z-distribution c) not normal d)chi-square distribution

Work Step by Step

a) The sample size is large (at least 30), hence the distribution is roughly normal. Standard deviation is unknown hence we will have to use t-distribution to estimate $\mu$. b)The sample size is large (at least 30), hence the distribution is roughly normal. Standard deviation is known hence we will have to use z-distribution to estimate $\mu$. c) The distribution is not normal, hence we cannot estimate a confidence interval. d) The distribution is normal, hence we can use the chi-square distribution to estimate $\sigma$'s confidence interval.
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