S1 Maths halp!!

a) if the machine "cuts to within 10 grams of any set weight" that means that the spread is 20 grams. as a rule of thumb you can say that 3 standard deviations either side of the mean will capture pretty much all the data... so 6 standard deviations = 20 grams approximately.

Ah okay so then you have to do 20/6 to get the answer. Thanks!
Do you know about the other ones?

have visitors so have to go