NASA is conducting an experiment to find out the fraction of people who black out at G forces greater than 6. In an earlier study, the population proportion was estimated to be 0.32.
1. How large a sample would be required in order to estimate the fraction of people who black out at 6 or more Gs at the 85% confidence level with an error of at most 0.03? Round your answer up to the next integer.

Respuesta :

Answer:

The sample that would be required in order to estimate the fraction of people who black out at 6 or more Gs is of size 502.

Step-by-step explanation:

The (1 - α)% confidence interval for population proportion p is:

[tex]CI=\hat p\pm z_{\alpha/2}\times \sqrt{\frac{\hat p(1-\hat p)}{n}}[/tex]

The formula to calculate the margin of error is,  

[tex]MOE=z_{\alpha/2}\times \sqrt{\frac{\hat p(1-\hat p)}{n}}[/tex]

The given information is, [tex]\hat p[/tex] = 0.32 and margin of error = 0.03.

The z-value for 85% confidence level is,

[tex]z_{\alpha/2}=z_{0.15/2}=z_{0.075}=1.44[/tex]

*Use a z-table for the z-value.

Then the sample size n is given by,

[tex]MOE=z_{\alpha/2}\times \sqrt{\frac{\hat p(1-\hat p)}{n}}[/tex]

       [tex]n=[\frac{z_{\alpha/2}\times \sqrt{\hat p(1-\hat p)}}{MOE} ]^{2}[/tex]

          [tex]=[\frac{1.44\times \sqrt{0.32(1-0.32)}}{0.03}]^{2}[/tex]

          [tex]=(22.392)^{2}\\=501.402\\\approx502[/tex]

Thus, the sample that would be required in order to estimate the fraction of people who black out at 6 or more Gs is of size 502.