In an engineering class, students want to determine the difference in the mean strength between two different types of building materialsType A, which is relatively inexpensive, and Type B, which is slightly more expensive. The students take a random sample of 60 of the Type A building material and a random sample of 26 of the Type B building material. Given the mean strength for each sample, the students construct a 95% confidence interval for the difference in population means. A button hyperlink to the SALT program that reads: Use SALT. (a) Determine the degrees of freedom for the conservative approach for finding the t critical value. (b) Find the t critical value associated with 95% confidence. (Use a table or technology. Round your answer to two decimal places.)