Answer:
The maximal margin of error associated with a 99% confidence interval for the true population mean backpack weight is 4.81 ounces
Step-by-step explanation:
We have that to find our
level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of
.
So it is z with a pvalue of
, so 
Now, find the margin of error M as such

In which
is the standard deviation of the population and n is the size of the sample.
So

The maximal margin of error associated with a 99% confidence interval for the true population mean backpack weight is 4.81 ounces