Assume that a large pile of split firework has a normal distribution of weights with a standard deviation o=3.0lbs . a random sample of n=20 pieces is collected and the mean piece weight is found to be x=6.3lbs

False... unless the numbers are both positive.

Step-by-step explanation:

-3 + 3 = 0.

Two positive numbers will never equal zero (as long as they are both not zero.

If you take a positive number and then add the negative version of that number, it will equal zero. For example, -1 + 1 = 0, -5 + 5 = 0, -1591 + 1591 = 0