Problem 1.65 Compute the sample mean, sample variance and sample standard deviation for the cadmium levels displayed in Problem 1.19. Problem 1.66 Refer to the weekly 2002 return data for GE listed in Table 1.20, Section 1.11. Use a statistical software package to compute:

(a) the sample mean of the 2002 GE returns.

(b) the sample standard deviation of the 2002 GE returns.

(c) Compare these results to the mean and standard deviation of the 1999 GE returns given in Table 1.13. Problem 1.67 Refer to the weekly 2002 return data for PTTRX listed in Table 1.20, Section 1.11. Use a statistical software package to compute:

(a) the sample mean of the 2002 PTTRX returns.

(b) the sample standard deviation of the 2002 PTTRX returns.

(c) Compare these results to the mean and standard deviation of the 1999 PTTRX returns given in Table 1.13.