Posted by Stephanie on .
Crunchy Corn Chips are packaged in bags labeled "net weight 10 ounces." In fact, the weight of a bag of Crunchy Corn Chips follows a normal distribution with mean ì ounces and standard deviation ó ounces. Worried about customer complaints and potential lawsuits, the manufacturers decided that no more than 0.5% of bags of Crunchy Corn Chips should be underweight. There are two possible adjustments that can be made: change the mean setting on the filling machines while leaving the standard deviation constant, or leave the mean at 10.4 ounces and try to adjust the standard deviation of 0.26 ounces. Describe the necessary adjustments under each of these two plans. Which do you think is more feasible? Explain.

Math 
Reiny,
Stephanie
Here is a really neat applet that will take the place of your zscore tables
http://davidmlane.com/hyperstat/z_table.html
You can experiment with both graphs.
Since you want .5% of the bags to be underweight, you are looking for an
"area" of .495 (I took .5  .005)
On the second graph, enter 0.495 in the area
and 10.4 and .26 into the mean and sd boxes.
click on "below"
Change the mean and sd entries and see what happens.