Question

Problem 3

The melting point of gold is known to be approximately 1,060 degrees centigrade. This is, of

course, an average figure, for unavoidable ‘experimental error’ causes more or less variation

from this figure whenever the test is actually performed. The best measure of these variations is

the standard deviation. Suppose this has been calculated from a large series of tests (assume n =

100), and found to be 3 degrees centigrade. Due to the recent increase in the price of gold,

special attention may be necessary to confirm that a product is actually gold. Suppose an

investigator is analyzing an unknown metal, and a test shows its melting point to be 1,065

degrees centigrade.

a) Explain why we can describe these data using a normal probability distribution.

b) What is the probability that a sample of gold would show a melting point as different from its

average as 1,065 degrees centigrade?

c) Is it likely that this unknown metal is gold? Justify using the probability.

Answer 1