A study is to be conducted of the percentage of homeowners who own at least two television sets. At least how large a sample is required if we wish to be 99% confident that the error in estimating this quantity is less than 0.019



Answer :

Answer:

The minimum sample size required is 4610.

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 margin of error for this interval is:

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

It is provided that a 99% confidence interval is computed to estimate the percentage of homeowners who own at least two television sets.

Assume that 50% of the homeowners own at least two television sets.

So, the sample proportion is, [tex]\hat p=0.50[/tex].

The critical value of z for 99% confidence interval is:

[tex]z_{\alpha/2}=z_{0.01/2}=z_{0.005}=2.58[/tex]

*Use a z-table for the critical value.

The margin of error is given as, MOE = 0.019.

Compute the value of n as follows:

[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{2.58\times \sqrt{0.50(1-0.50)}}{0.019}]^{2}[/tex]

  [tex]=(67.8947)^{2}\\=4609.6903\\\approx4610[/tex]

Thus, the minimum sample size required is 4610.