How many pounds a statistician can bench press is normally distributed with a mean of 139 and standard deviation of 46. If Scott can bench 145 pounds, approximately what percentage of statisticians can bench more than Scott

Respuesta :

Answer:

The percentage is  [tex]P(X > 145 ) = 44.811\%[/tex]

Step-by-step explanation:

From the question we are told that

   The  mean is  [tex]\mu = 139[/tex]

   The standard deviation is  [tex]\sigma = 46[/tex]

   The weight Scott can bench is  x =  145 pounds

Generally the percentage of statisticians that can bench more than Scott is mathematically represented as

      [tex]P(X > x ) = P(\frac{X - \mu }{\sigma } > \frac{x- 139 }{46 } )[/tex]

 =>  [tex]P(X > 145 ) = P(\frac{X - \mu }{\sigma } > \frac{145 - 139 }{46 } )[/tex]

[tex]\frac{X -\mu}{\sigma }  =  Z (The  \ standardized \  value\  of  \ X )[/tex]

    [tex]P(X > 145 ) = P(Z > 0.13043)[/tex]

From the z table  

The area under the normal curve to the right corresponding to 0.13043  is  

     [tex]P(Z > 0.13043) = 0.44811[/tex]

=>  [tex]P(X > 145 ) = 0.44811[/tex]

Converting to percentage

     [tex]P(X > 145 ) = 0.44811 * 100[/tex]

=>  [tex]P(X > 145 ) = 44.811\%[/tex]