9. Incorrect. The answer is true, not false.


First of all, you have to calculate the expected value of the sample. It is simply the average of the prices. Let P the copper price. The expected value μ is:



Second, you have to calculate the standard deviation. The formula of the variance of the sample prices is:


where “n” is the number of observations. Applying this formula to the information in the table:


The standard deviation is: (σ2)0.5 = 17.49.


The standardized prices can be obtained by applying the following formula to each sample price in the table:



The result is: