Posted by tonja on Thursday, February 9, 2012 at 12:11pm.
If the mean value of the weight of a particular brand of dog food is 20.6 lb and the standard deviation is 1.3, assume a normal distribution and calculate the amount of product produced that falls below the lower specification value of 19.7 lb.

statistics  PsyDAG, Friday, February 10, 2012 at 12:03pm
Z = (scoremean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to the Z score. 
statistics  Elizabeth, Sunday, February 17, 2013 at 3:44pm
19.720.6/1.3 = .69 = 25% or 25 percent are less than 19.7 pounds