Three different bottles of vinegar were analyzed by the same…

Three different bottles of vinegar were analyzed by the same analyst for percentage acetic acid content. The following results were obtained. Bottle no.1 Bottle no. 2 Bottle no.3 3.88 [F] 8.13 3.92 [G] 8.19 3.75 [H] 8.17 3.84 [I] 8.05 3.91 [J] 8.21 Calculate the  margin of error for the 95% confidence interval for sample 2 if s→σ.

Which step(s) is/are NOT required in the practice of weighin…

Which step(s) is/are NOT required in the practice of weighing by difference? Weigh a capped bottle containing the dry reagent. Quickly pour some of the dry reagent from the weighing bottle into a receiver. Weigh the receiver containing the dry reagent. Recap the bottle that now contains less of the dry reagent. Reweigh the capped bottle that contains less of the dry reagent.