When n=343 college students are randomly selected and surveyed, it is found that x=110 own a car. Find a 99% confidence interval (CI) and margin of error (ME) for the true proportion of all college students who own a car.

Respuesta :

Answer:

The margin of error will be "0.65". A further explanation is provided below.

Step-by-step explanation:

The given values are:

n = 343

x = 110

At 99% confidence level,

[tex]\alpha = 1-99[/tex]%

  [tex]=1-0.99[/tex]

  [tex]=0.01[/tex]

then,

[tex]\frac{\alpha}{2} =\frac{0.01}{2}[/tex]

  [tex]=0.005[/tex]

or,

[tex]Z_{\frac{\alpha}{2} }=Z_{0.005}[/tex]

     [tex]=2.576[/tex]

Now,

The point estimate will be:

⇒  [tex]\hat{P}=\frac{x}{n}[/tex]

⇒      [tex]=\frac{110}{343}[/tex]

⇒      [tex]=0.321[/tex]

or,

⇒  [tex]1-\hat{P}=1-0.321[/tex]

⇒            [tex]=0.679[/tex]

The margin of error will be:

⇒  [tex]E=Z_{\frac{\alpha}{2} }\times \sqrt (\frac{(\hat{P}\times (1 - \hat{P})) }{n} )[/tex]

On substituting the above values, we get

⇒      [tex]=2.576\times \sqrt{\frac{0.321\times 0.679}{343} }[/tex]

⇒      [tex]=2.576\times \sqrt{\frac{0.217959}{343} }[/tex]

⇒      [tex]=0.065[/tex]

hence,

⇒  [tex]\hat{P}-E<p<\hat{P}+E[/tex]

⇒  [tex]0.321-0.065<p<0.321+0.065[/tex]

⇒  [tex]0.256,0.386[/tex]