a researcher wishes to estimate the mean number of miles driven by 4-year-old cars. The population standard deviation of miles driven by all chevy owners is 15,500 milesl how man cars must be sampled so that a 92% confidence interval will have a margin of error of 1000 miles?

Respuesta :

Answer:

The sample size must be approximately 1304.      

Step-by-step explanation:

We are given the following in the question:

Population standard deviation = 15,500 miles

We have to construct a 92% confidence interval with margin of error of 1000 miles.

Margin of error =

[tex]z_{critical}\times \dfrac{\sigma}{\sqrt{n}}[/tex]

[tex]z_{critical}\text{ at}~\alpha_{0.02} = \pm 2.33[/tex]

Putting values, we get,

[tex]2.33\times \dfrac{15500}{\sqrt{n}} = 1000\\\\\sqrt{n} = 2.33\times \dfrac{15500}{1000} \\\sqrt{n} = 36.115\\n = 1304.29\\n\approx 1304[/tex]

The sample size must be approximately 1304.