Elementary Statistics (12th Edition)

Published by Pearson
ISBN 10: 0321836960
ISBN 13: 978-0-32183-696-0

Chapter 8 - Hypothesis Testing - 8-2 Basics of Hypothesis Testing - Basic Skills and Concepts - Page 398: 29


a) For $H_0$, $p=0.5 $; For $H_1$, $p\gt0.5$ b) $0.01$ c) Normal d) Right-tailed e) $1.00$ f) $0.1587$ g) $2.33$ h) $0.01$

Work Step by Step

a) The null hypothesis is the average fraction of girls, which is $0.5$, and the alternative hypothesis is that more than 50 percent of births are girls, which is $p\gt0.5$. b) $α$ is the significance level, which the problem says is $0.01$. c) We can see that the sample distribution of the sample statistic is a normal distribution. d) There are more girls in the survey, so the two-test is right tailed. e) The problem says that the sample statistic is $1.00$. f) Using the table of z-scores, we can find that: $P=1−0.8413=0.1587$ g) Using the table of z-scores, we can find that the critical value is $2.33$. h) The significance level is $0.01$, hence the area of the critical region is $0.01$.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.