Volume and standard deviation??? please help!!!?

When delivering 10 mL of water from the graduated cylinder to the vial, the masses of water actually delivered for each of your 5 trials were: 9.695 g, 9.871 g, 9.807 g, 10.036 g, and 9.809 g. Calculate the average volume of water dispensed and the standard deviation of your measurements. Assume the temperature of the water is 25 ̊C and the density is 0.99704 g/mL.

Volume and standard deviation??? please help!!!?
volume = mass / density.





So find the average mass of all your trials. Which comes out to 9.844. And now just plug it into the formula.





volume = 9.844/0.99714 = 9.873mL





Standard deviation





the formula looks a little more complex than this but this is the general idea.


s= [ xi-x^2/n-1] ^ 1/2


xi = individual result (trials)


x= the average


n=total number of measurements (number of trials)





s= [(9.695-9.844)^2+(9.871-9.844)^2+(9.807-... / 5-1] ^ (1/2) = .125 mL





I had to answer the exact same question but with different numbers. I'm pretty sure this is right.
Reply:hmmm... i never learned standard deviation in chem, only in psych....





first of all, i'm assuming when you said grams for all the measurements that follow that you meant mL





the avg would be 9.844 mL, i'm guessing you know how to do that....





here's how you do standard deviation:





first, subtract each trial from the average... then square all those answers and add them together. this is your variance





i got .0624 for the variance. then, take the square root of this answer (because it is currently in squared mL, which isn't really of use to anybody)





the standard deviation is .2498mL





idk if it's the same thing in chemistry, tho.