We want to obtain a sample to estimate a population mean. Based on previous evidence, researchers believe the population standard deviation is approximately σ
=
20.4
. We would like to be 99.5% confident that the estimate is within 4 of the true population mean. How large of a sample size is required?

i wish i could you, i have no idea how to answer this

step-by-step explanation:

a.for lorena 14 hours makes $126   for 16 hours she makes 144

for julie 6 hours makes $72 for 21 hours its $252

b. julie makes more money than lorena julie makes $12 an hour and lorena makes $9  

.

the easiest way to do these would be to solve the equations. if you can solve the equation than you can solve these problems.