A newspaper article about the results of a poll states: "In theory, the results of such a poll, in 99 cases out of 100 should differ by no more than 5 percentage points in either direction from what would have been obtained by interviewing all voters in the United States." Find the sample size suggested by this statement.

Respuesta :

Answer:

The sample size 'n' =15

Step-by-step explanation:

Explanation:-

given data A newspaper article about the results of a poll states: "In theory, the results of such a poll, in 99 cases out of 100

Sample proportion 'p' = 99/100 =0.99

Given Margin of error = 5% =0.05

The margin of error is determined by

[tex]M.E = \frac{Z_{\frac{\alpha }{2} }\sqrt{p(1-p)} }{\sqrt{n} }[/tex]

The Z-score of 95% of level of significance

[tex]Z_{\frac{0.05}{2} } = Z_{0.025} =1.96[/tex]

[tex]0.05 =\frac{1.96 X \sqrt{0.99(0.01)} }{\sqrt{n} }[/tex]

Cross multiplication, we get

[tex]\sqrt{n} =\frac{1.96 X \sqrt{0.99(0.01)} }{0.05 }[/tex]

[tex]\sqrt{n} = 3.90[/tex]

Squaring on both sides, we get

n = 15.21

Final answer:-

Sample size 'n' = 15