10.67 Referring to Applied Example 10.11:

a. The “Variances  Unequal” is equivalent to making no assumption about the variances.

Verify the value reported for the estimated standard error, SE of Difference.

b. Verify the t-value.

c. What is the range of possible values for df for this study?

d. Explain how df  17.57 was obtained.

e. What df value would you use based on the material presented in Section 10.4?

f. Explain why the t-value of 6.98 is said to be

“highly significant.”