An experiment was conducted to compare the strength of welds
produced by four different welding techniques. Each technique
was used to weld five pairs of metal plates. The average
strengths for the five welds for each technique were: Technique:
A B C D 69 83 75 71 The estimate of experimental error variance
was MSE = 15 with 16 degrees of freedom. Apply the Tukey method
to the data using an overall error rate of 0.05 in order to
compare all pairs of treatments. Which treatments produce the
same average strength?