Question

A random sample of five Galaxy 8 smartphones is selected from the production line after final assembly, and the result of the weight control measurement is (in grams) 155.1, 154.8, 155.5, 155.3, and 154.6.What are the average weight, its uncertainty (i.e. the standard deviation of the mean), and the fractional uncertainty

Answer 1

a. Mean = 155.1 grams

b. Standard deviation = 0.37

c. Fractional uncertainty = 0.074

Explanation:

a. Average weight

This is same as the mean weight;

Mathematically, that would be; sum of the weights/ the number of weights

= (155.1 + 154.8 + 155.5 + 155.3 + 154.6)/5 = 775.3/5 = 155.06 which is approximately 155.1

b. Standard deviation

Mathematically; we calculate that using the formula;

√{(x-mean)^2/(N-1)}

Please check attachment for for the complete breakdown of this

c. Fractional uncertainty

= Standard deviation/number of measurements = 0.37/5 = 0.074