Duke's Brand Dog Treats claim to contain 53 treats in each of its jumbo packages of treats. The standard deviation for the number of treats in each package is 20 ( you can think of this claim as representing the whole population of jumbo packages dog treats ) . You decide to test this because you ( and your dog ) think the jumbo packages of treats contain a different number of treats than the Duke brand claims. You count the number of treats in a sample of 16 jumbo packages and find that their average is 39 treats per package. Calculate a one sample z - test to test whether your sample of dog treats reflects the population ( what the company claims ) . Put your value below and round your answer to 2 decimal places