Hockey pucks used in professional hockey games must weigh between 5.5 and 6 ounces. if the weight of pucks manufactured by a particular process is bell-shaped and has mean 5.75 ounces, how large can the standard deviation be if 99.7% of the pucks are to be usable in professional games?

Respuesta :

Solution: The weight of pucks manufactured by a particular process is bell-shaped and has mean 5.75 ounces

Therefore, we can use the Empirical Rule to find the standard deviation. Empirical Rule states that approximately 99.7% of all observations fall within three standard deviations of the mean.

Also we know that the acceptable range is between 5.5 and 6

So [tex]5.5=5.75-3\times SD[/tex]

     [tex]3\times SD=5.75-5.5[/tex]

     [tex]SD=\frac{0.25}{3} =0.083[/tex]

Also [tex]6=5.75+3\times SD[/tex]

       [tex]3\times SD=6-5.75[/tex]

       [tex]SD=\frac{0.25}{3} =0.083[/tex]    

So if 99.7% of the pucks are to be usable in professional games, the standarddeviation should be 0.083.