Researchers are interested in estimating the percentage of Americans who will get a flu shot this year. How many Americans should be surveyed to be 80% confident that the sample proportion of Americans who will get a flu shot this year is within 0.100 of the population proportion Assume we have a prior estimate of 45%. Round your z critical value to four decimal places.

Respuesta :

Answer:

The sample size bedded is   [tex]n =41[/tex]

Step-by-step explanation:

From the question we are told that

   The margin of error is  [tex]E = 0.100[/tex]

    The sample proportion is  [tex]\^ p = 0.45[/tex]

From the question we are told the confidence level is  80% , hence the level of significance is    

      [tex]\alpha = (100 - 80) \%[/tex]

=>   [tex]\alpha = 0.20[/tex]

Generally from the normal distribution table the critical value  of  [tex]\frac{\alpha }{2}[/tex] is  

   [tex]Z_{\frac{\alpha }{2} } =  1.282[/tex]

Generally the sample size is mathematically represented as  

    [tex]n = [\frac{Z_{\frac{\alpha }{2} }}{E} ]^2 * \^ p (1 - \^ p ) [/tex]

=> [tex]n = [\frac{1.282}{ 0.100} ]^2 *0.45 (1 - 0.45 ) [/tex]

=> [tex]n =41[/tex]