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Community Involvement Claim: Three-fourths of all adults believe that it is important to be involved
in their communities. Based on a USa Today/Gallup poll of 1021 randomly selected adults, 89%
believe that it is important to be involved in their communities. find the value of the test statistic.


Sagot :

Using the z-distribution, it is found that the value of the test statistic is z = 10.33.

At the null hypothesis, it is tested if the proportion is of [tex]\frac{3}{4} = 0.75[/tex], hence:

[tex]H_0: p = 0.75[/tex]

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

[tex]H_1: p \neq 0.75[/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 = 0.75, \overline{p} = 0.89, n = 1201[/tex]

Hence:

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

[tex]z = \frac{0.89 - 0.75}{\sqrt{\frac{0.75(0.25)}{1021}}}[/tex]

[tex]z = 10.33[/tex]

A similar problem is given at https://brainly.com/question/24330815