Question

suppose 160 geology students measure the mass of an ore sample. due to the human error and limitations in the reliability of the balance not all the readings are equal the result are found to closely approximate a normal curve with the mean 85 g and the standard deviation 1 g . use the symmetry of the normal curve and the empirical rule as needed to estimate the number of students reporting readings more than 85 g

Answer 1

Empirical rule formula:

- 68% of data falls between 1 standard deviation about mean (34% on left side and 34% on right side)

- 95% of data falls between 2 standard deviations about mean (47.5% on left side and 47.5% on right side)

- 99.7% of data falls within 3 standard deviations from the mean.(49.85% on left side and 49.85% on right side).

According to the simmetry of the normal curve and the empirical rule, 49.85 % of students reported a value greater than 85 g. It implies 80 geology students reported a value greater than 85 g.