How do I compute the sample mean difference in weight?

Question

amistre64 · Answer

if im remembering;  its pretty much taking the difference between 1 weight from all the others; then doing the same for another, then another, until all weights have been differenced from every other weight ; then divide by how many times you had to do it

amistre64 · Answer

but without some more context, thats the best idea i got :)

anonymous · Answer

attachment

anonymous · Answer

I know I have a right (4.167 or 4.2 lbs.)
But I am stuck on B and C

amistre64 · Answer

row 3 is the data set

amistre64 · Answer

$$\sigma\approx s^2/\sqrt n$$
hmm, id have to chk this but thats when im thinking for standard error

im thinking s is an unbiased estimator of sigma for the sample

amistre64 · Answer

s/sqrt(n) ... not s^2

amistre64 · Answer

you do know how to calculate a sample standard deviation right?

anonymous · Answer

I am jsut not understanding how to get B. I know that whatever my answer is from B is divided by the sq oot of n to get c.

amistre64 · Answer

what was the sample mean?

amistre64 · Answer

$$\large s=\frac{\sum(x-\bar x)^2}{n-1}$$

anonymous · Answer

Thank you :) I think I can get it from here...we'll see.

amistre64 · Answer

the sample standard deviation is a biased estimator but is commonly used as a point estimator of the populations standard deviation.  Otherwise it might be expecting a chi^2 distribution