Refer to the Analytical Chemistry (May 2010) study in which medical researchers tested a new method of typing blood using lost cost paper, Exercises 10.6 and 10.22. Recall that the data was used to fit the straight-line model relating wicking length (millimeters) to x = antibody concentration. A y = portion of the SPSS printout not previously shown is displayed on p. 511. Use the information on the printout to find a 95% confidence interval for the slope of the line. Give a practical interpretation of the interval.

**Data from Exercise 10.6**

In Analytical Chemistry (May 2010), chemical engineers tested a new method of typing blood using lost cost paper. Blood drops were applied to the paper and the rate of absorption (called blood wicking) was measured. The table below gives the wicking lengths (millimeters) for six blood drops, each at a different antibody concentration. Let y = wicking length and x = antibody concentration.