Elementary Statistics (12th Edition)

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

Chapter 8 - Hypothesis Testing - Review - Cumulative Review Exercises - Page 436: 10

Answer

There is sufficient evidence to support that less than half of the adults answer yes.

Work Step by Step

$H_{0}:p=50$%=0.5. $H_{a}:p<0.5$ $\hat{p}$ is the number of objects with a specified value divided by the sample size. Hence $\hat{p}=0.372.$ The test statistic is:$z=\frac{\hat{p}-p}{\sqrt{p(1-p)/n}}=\frac{0.372-0.5}{\sqrt{0.5(1-0.5)/1003}}=0.67.$ The P is the probability of the z-score being less than -8.11, hence:P=0.0001. If the P-value is less than $\alpha$, which is the significance level, then this means the rejection of the null hypothesis. Hence:P=0.0001 is less than $\alpha=0.01$, hence we reject the null hypothesis. Hence we can say that there is sufficient evidence to support that less than half of the adults answer yes.
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