Suppose in order for a bill to pass in Congress, 50% of voters must be in favor of it. In a random sample of 150 voters, 62 said that they were in favor of a new bill. State the p-value assuming the alternative hypothesis is Ha ≠.50 (Round to the nearest hundredth.)

Respuesta :

Using the z-distribution, it is found that the p-value is of 0.03.

At the null hypothesis, it is tested if the proportion is of 0.5, that is:

[tex]H_0: p = 0.5[/tex]

At the alternative hypothesis, it is tested if the proportion is different of 0.5, that is:

[tex]H_a: p \neq 0.5[/tex]

The test statistic is given by:

[tex]z = \frac{\overline{p} - p}{\sqrt{\frac{p(1-p)}{n}}}[/tex]

In which:

  • [tex]\overline{p}[/tex] is the sample proportion.
  • p is the proportion tested at the null hypothesis.
  • n is the sample size.

For this problem, the parameters are: [tex]p = 0.5, n = 150, \overline{p} = \frac{62}{150} = 0.4133[/tex]

Hence, the value of the test statistic is:

[tex]z = \frac{\overline{p} - p}{\sqrt{\frac{p(1-p)}{n}}}[/tex]

[tex]z = \frac{0.4133 - 0.5}{\sqrt{\frac{0.5(0.5)}{150}}}[/tex]

[tex]z = -2.12[/tex]

The p-value is found using a z-distribution calculator, with z = -2.12 and a two-tailed test, as we are testing if the mean is different of a value, hence it is of 0.03.

To learn more about the use of the z-distribution for hypothesis tests, you can take a look at https://brainly.com/question/16313918