Statistics: Best formula for average weight gain?

I did a survey of nearly 1000 people. In the survey I have the starting weight and ending weight (the participants were trying to gain weight).
What is the best formula for eliminating the most errors in finding the average weight gain?
Right now I am using the standard elementary formula for finding a mean: (Total [...]

what is the formula for calculating cash paid for wages and salaries?

calculate cash paid for wages and salaries:
salaries expense = $168,000
salaries payable, january 1 = $ 6,400
salaries payable, december 31 = $ 10,600
a. $168,000
b. 174,400
c. 157,400
d. 172,200
e. 163,800
thanks for teaching me. appreciate it sooo much.

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