Answer :
Answer:
0.0073 < 0.05, which means that we reject the null hypothesis and conclude that the true proportion of interest is higher than 0.7.
Step-by-step explanation:
Conduct a test to determine whether the true proportion of interest is higher than 0.7.
This means that the null hypothesis is: [tex]H_{0}: p = 0.7[/tex]
And the alternate hypothesis is: [tex]H_{a}: p > 0.7[/tex]
The test statistic is:
[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, [tex]\sigma[/tex] is the standard deviation and n is the size of the sample.
0.7 is tested at the null hypothesis:
This means that [tex]\mu = 0.7, \sigma = \sqrt{0.7*0.3}[/tex]
The sociologist found that 375 of the 500 travelers randomly selected and interviewed indicated that the airports were safe.
This means that [tex]n = 500, X = \frac{375}{500} = 0.75[/tex]
Value of the z-statistic:
[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
[tex]z = \frac{0.75 - 0.7}{\frac{\sqrt{0.7*0.3}}{\sqrt{350}}}[/tex]
[tex]z = 2.44[/tex]
P-value of the test:
Probability of z being larger than 2.44, that is, a proportion larger than 0.75.
This is, looking at the z-table, 1 subtracted by the pvalue of Z = 2.44. S
Z = 2.44 has a pvalue of 0.9927
1 - 0.9927 = 0.0073
0.0073 < 0.05, which means that we reject the null hypothesis and conclude that the true proportion of interest is higher than 0.7.