At 95% confidence, how large a sample should be taken to obtain a margin of error of .03 for the estimation of the population proportion? Assume past data are not available for developing a planning value for p*.

Respuesta :

Answer:

The sample should be 1,068.

Step-by-step explanation:

Consider the provided information.

Confidence level is 95% and margin of error is 0.03.

Thus,

1-α=0.95

α=0.05, E=0.03 and planning value [tex]\hat p=0.5[/tex]

Formula to calculate sample size is: [tex]n=\frac{\hat p(1-\hat p)(z_{\alpha/2})^2}{E^2}[/tex]

From the table we can find:  

[tex]z_{\alpha/2}=z_{0.05/2}\\z_{0.025}=1.96[/tex]

Substitute the respective values in the above formula we get:

[tex]n=\frac{0.5(0.5)(1.96)^2}{(0.03)^2}[/tex]

[tex]n=\frac{0.25(1.96)^2}{(0.03)^2}\approx 1067.111[/tex]

Hence, the sample should be 1,068.

The Answer should really be 1,068.
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