Question 1:

Cardiac pacemakers contain electrical connections that are platinum pins soldered onto a substrate. The question of interest is whether different operators produce solder joints with the same strength. Twelve substrates are randomly assigned to four operators. Each operator solders four pins on each

substrate, and then these solder joints are assessed by measuring the shear strength of the pins. Data from T. Kerkow.

Part a) Analyze these data to determine if there is any evidence that the operators produce different mean shear strengths.

Part b) Workers 1 and 2 were experienced, whereas workers 3 and 4 were novices. Find a contrast to compare the experienced and novice workers and test the null hypothesis that experienced and

novice works produce the same average shear strength.

Part c) Test the null hypothesis that all pairs of workers produce solder joints with the same average strength against the alternative that some workers produce different average strengths.

Data is available in:

http://users.stat.umn.edu/~gary/book/fcdae.data/pr3.1

we are using R to program.