You have two scales for measuring weights in a chemistry lab

You have two scales for measuring weights in a chemistry lab Both scales give answers that vary a bit m repeated weighing of the same item If the true weight of a compound is 2.00 grams (g), the first scale produces readings X that have a mean of 2 000 g and standard deviation 0.002 g The second scale\'s readings Y have a mean of 2 001 g and standard deviation 0.001 g. What are the mean and standard deviation of the difference Y-X between the readings? (The readings X and Y are independent.)

Solution

The mean and standard deviation of the difference Y-X between the readings.

The mean of the first scaleX is 2000g and mean of the second scale Y is 2001 g.

the mean difference y-x=2001-2000=1g

The std deviation of the first scale is 0.002g and second scale is 0.001g

the difference of the std deviation is Y-X= 0.001-0.002=-0.001g