Question

VCalculate the mean, standard deviation and relative standard deviation, for both the molarity of your KMnO4 solution and the % Fe in your unknown solid.   For both of these, calculate a range which contains the true mean at the 95% confidence level.

Answer 1

let us fing the RSD for the following set of numbers:
49, 51.3, 52.7. 55.8

Step 1: Find the mean standard deviation of your sample. Std dev = 2.8437065 (or 2.84 rounded to 2 decimal places).

Step 2: Multiply Step 1 by 100. Set this number aside for a moment.
2.84 * 100 = 284

Step 3: Find the sample mean, x̄. The sample mean is:
(49 + 51.3 + 52.7 + 55.8) / 4 = 208.8/4 = 52.2.

Step 4: Divide Step 2 by the absolute value of Step 3.
284/|52.2| = 5.44

The RSD = 52.2 ±5.4%
(Note: RSD is expressed as a percentage.)