Repeated lab measurements. A laboratory kit states that the standard deviation of its results can be expected to vary with σ = 1 unit. A lab technician takes four measurements using this kit.

(a) What is the value of the standard deviation of the of the four measurements taken with this kit?

(b) Explain to a lay person the advantage of reporting the average of four measurements rather than using a single measurement.

(c) How many times must we repeat the measurement before we obtain a standard deviation of the mean measurement of 0.2 units? [Hint: Rearrange the formula to solve for n.]