A normally distributed population of package weights has a mean of 63.5 g and a standard deviation of 12.2 g. XN(63.5,12.2) a. What percentage of this population weighs 66 g or more

Respuesta :

Answer:

The percentage  is  %z [tex]= 41.9[/tex]%    

Step-by-step explanation:

From the question we are told that

     The mean is  [tex]\mu = 63.5 \ g[/tex]

     The  standard deviation is  [tex]\sigma = 12.2 \ g[/tex]

      The  random number is  x  = 66 g

Given the the population is normally distributed

   The  probability is mathematically represented as

        [tex]P(X > 66 ) = P(\frac{X - \mu }{\sigma} > \frac{x - \mu }{\sigma } )[/tex]  

Generally the z-score for this population is mathematically represented as

         [tex]Z = \frac{ X - \mu}{ \sigma}[/tex]

  So

      [tex]P(X > 66 ) = P(Z > \frac{66 - 63.5 }{12.2 } )[/tex]  

      [tex]P(X > 66 ) = P(Z > 0.2049 )[/tex]  

Now the z-value for 0.2049 from the standardized normal distribution table is  

     [tex]z = 0.41883[/tex]

=>    [tex]P(X > 66 ) = 0.41883[/tex]  

The  percentage  is

     % z     [tex]= 0.41883 * 100[/tex]  

     %z   [tex]= 41.9[/tex]%