An insurance company checks police records on 582 accidents selected at random and notes that teenagers were at the wheel in 91 of them. Which is a correct 90% confidence interval for the proportion of all auto accidents that involve teenage drivers

Respuesta :

Answer:

The 90% confidence interval is  [tex]0.1316 <  p <  0.1812[/tex]

Step-by-step explanation:

From the question we are told that

   The sample size is  n  =  582

   The number of teenagers at the wheel is k = 91

Generally the sample proportion is mathematically represented as

          [tex]\^ p = \frac{k}{n}[/tex]

=>       [tex]\^ p = \frac{91}{582}[/tex]

=>      [tex]\^ p = 0.1564[/tex]

From the question we are told the confidence level is  90% , hence the level of significance is    

      [tex]\alpha = (100 - 90 ) \%[/tex]

=>   [tex]\alpha = 0.10[/tex]

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

   [tex]Z_{\frac{\alpha }{2} } =  1.645[/tex]

Generally the margin of error is mathematically represented as  

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

=>  [tex]E =  1.645 * \sqrt{\frac{0.1564  (1- 0.1564)}{582} } [/tex]

=>  [tex]E =  0.0248 [/tex]

Generally 95% confidence interval is mathematically represented as  

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

=>   [tex]0.1564  -0.0248 <  p <  0.1564  + 0.0248[/tex]

=>   [tex]0.1316 <  p <  0.1812[/tex]