In a survey of 1,003 adults concerning complaints about restaurants, 732 complained about dirty or ill-equipped bathrooms and 381 complained about loud or distracting diners at other tables.
a. Construct a 95% confidence interval estimate for the population proportion of adults who complained about dirty or ill-equipped bathrooms )
b. Construct a 95% confidence interval estimate for the population proportion of adults who complained about loud or distracting diners at other tables.
c. How would the manager of a chain of restaurants use the results of (a) and (b)?

Respuesta :

Answer:

a

[tex]0.716 < p < 0.744[/tex]

b

[tex]0.3498 < p < 0.4089[/tex]

c

 With the result obtained from a and b the manager can be 95 % confidence that the proportion of the population that complained about dirty or ill-equipped bathrooms are within the interval obtained at  a

and that

the proportion of the population that complained about loud or distracting diners at other tables are within the interval obtained at  b

Step-by-step explanation:

From the question we are told that

The sample size is  [tex]n = 1003[/tex]

The number that complained about dirty or ill-equipped bathrooms is [tex]e = 732[/tex]

 The number that complained about loud or distracting diners at other tables is  [tex]q = 381[/tex]

Given that the the confidence level is  95% then the level of significance is mathematically represented as  

         [tex]\alpha = (100- 95)\%[/tex]

         [tex]\alpha = 0.05[/tex]

Next we obtain the critical value of  [tex]\frac{\alpha }{2}[/tex] from the normal distribution table , the value is  

         [tex]Z_{\frac{\alpha }{2} } = 1.96[/tex]

Considering question a

The sample proportion is mathematically represented as

           [tex]\r p = \frac{e}{n}[/tex]

=>        [tex]\r p = \frac{732}{1003}[/tex]

=>        [tex]\r p = 0.73[/tex]

Generally the margin of error is mathematically represented as

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

          [tex]E = 1.96* \sqrt{ \frac{ 0.73 (1- 0.73)}{1003} }[/tex]

          [tex]E = 0.01402[/tex]

The 95% confidence interval is  

        [tex]\r p - E < p < \r p +E[/tex]

        [tex]0.73 - 0.01402 < p < 0.73 + 0.01402[/tex]

        [tex]0.716 < p < 0.744[/tex]

Considering question b

The sample proportion is mathematically represented as

           [tex]\r p = \frac{q}{n}[/tex]

=>        [tex]\r p = \frac{381}{1003}[/tex]

=>        [tex]\r p = 0.3799[/tex]

Generally the margin of error is mathematically represented as

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

          [tex]E = 1.96* \sqrt{ \frac{ 0.3799 (1- 0.3799)}{1003} }[/tex]

          [tex]E = 0.0300[/tex]

The 95% confidence interval is  

        [tex]\r p - E < p < \r p +E[/tex]

        [tex]0.3798 - 0.0300 < p < 0.3798 + 0.0300[/tex]

        [tex]0.3498 < p < 0.4089[/tex]