"Currently, only 20 percent of arrested drug pushers are convicted", cried candidate AK in a campaign speech. "Elect me and you'll see a big increase in convictions" A year after his election a random sample of 144 case files of arrested drug pushers showed 36 convictions. For a right-tailed test, find the p-value. A. 0.12 B. 0.07 C. 0.06 D. 0.04

Respuesta :

Answer:

B. 0.07

Step-by-step explanation:

This is a hypothesis test for a proportion.

The claim is that the proportion of convicted drug pushers is significnalty higher than 20%.

Then, the null and alternative hypothesis are:

[tex]H_0: \pi=0.2\\\\H_a:\pi>0.2[/tex]

The sample has a size n=144.

The sample proportion is p=0.25.

[tex]p=X/n=36/144=0.25[/tex]

The standard error of the proportion is:

[tex]\sigma_p=\sqrt{\dfrac{\pi(1-\pi)}{n}}=\sqrt{\dfrac{0.2*0.8}{144}}\\\\\\ \sigma_p=\sqrt{0.001111}=0.0333[/tex]

Then, we can calculate the z-statistic as:

[tex]z=\dfrac{p-\pi}=\dfrac{0.25-0.2}{0.0333}=\dfrac{0.05}{0.0333}=1.5[/tex]

This test is a right-tailed test, so the P-value for this test is calculated as:

[tex]\text{P-value}=P(z>1.5)=0.066\approx0.07[/tex]