[clueless575]

1. Record the mass of the envelopes A-G in a data table
2. Each envelope contains between 3 and 26 paper clips
3. Record the mass of an empty envelope
4. Determine the number of paper clips in each of the envelopes
5. Determine the mass of a single paper clip

I have the mass of each envelope recorded, I am just not sure how to figure out the number of paper clips and mass of each paper clip.  The mass of each envelope are as follows:
A. 9.11 g
B. 12.81 g
C. 15.67 g
D. 23.30 g
E. 12.91 g
F. 7.21 g
G. 19.48 g
EMPTY: 3.44 g

please help me!!!

[Hunter2]

Show your own attempt.

Calculate the mass of the paper clips in each envelope? How many paper clips correspond to the highest mass and the lowest mass.

[clueless575]

Well I figured out e+np in which e is the envelope, p is the mass of one paper clip, and n is the paper clips in each envelope. I'm just not sure how to go about solving this or how to start it

[clueless575]

I've also tried subtracting two similar masses (12.91-12.81) but I'm just not sure what to do with the number.  And I have made a column subtracting the mass of the empty envelope from each mass to get the mass of just the paper clips

[Borek]

I've also tried subtracting two similar masses (12.91-12.81)

Good try, but I am afraid you are out of luck with these data.

Generally speaking one should expect the smallest difference to be a mass of a single clip. However, looks to me like that's not the case. If one clip weight is 12.91-12.81=0.10g, envelope F contains (7.21-3.44)/0.10≈38 clips, and you were told they contain at most 26. This makes me think envelopes B and D contain the same number of clips, and the difference is just an experimental error.

Best approach would call for using least squares method, which is probably way above what you are expected to use. What is the lowest mass difference (ignoring this unlucky 0.10g)? Try to assume this lowest difference is a single clip and see how many clips would other envelopes contain. If none of these numbers look reasonable (they should be close to integers and in the given range), assume it was two clips - and repeat...

[Arkcon]

Something that may help you understand this experiment better -- construct a graph.  Try to chart number of clips vs mass observed.  You'll spot outliers easier, and can justify on the chart, excluding them.  You'll get a formula for the best fit line (like Boreck: said,) and you'll be able to say just how good your answer is.