A direct mail company wishes to estimate the proportion of people on a large mailing list that will purchase a product. Suppose the true proportion is 0.07. If 343 are sampled, what is the probability that the sample proportion will be less than 0.11

Respuesta :

Answer:

The probability that the sample proportion will be less than 0.11 = .9982

Step-by-step explanation:

Given -

Suppose the true proportion is 0.07 .

true proportion [tex](\nu _{\widehat{p}})[/tex] = p = 0.07

q = 1 - p = 1 - 0.07 = 0.93  

n = 343

Standard deviation  [tex](\sigma _{\widehat{p}})[/tex] = [tex]\sqrt{\frac{p\times q}{n}}[/tex]   = [tex]\sqrt{\frac{0.07\times 0.93}{343}}[/tex]  = .0137

the probability that the sample proportion will be less than 0.11 =

[tex]P(\widehat{p}< 0.11)[/tex]   =  [tex]P(\frac{\widehat{p} - \nu _{\widehat{p}}}{\sigma _{\widehat{p}}}<\frac{ 0.11 - 0.07}{.0137})[/tex]   using[ [tex]z = \frac{\widehat{p} - \nu _{\widehat{p}}}{\sigma _{\widehat{p}}}[/tex]]

                     =  [tex](z< 2.91)[/tex]

                       =  .9982