Question

The slant shear test is widely accepted for evaluating the bond of resinous repair materials to concrete; it utilizes cylinder specimens made of two identical halves bonded at 30°. For 12 specimens prepared using wire-brushing, the sample mean shear strength (N/mm²) and sample standard deviation were 19.3 and 1.59, respectively, whereas for 12 hand-chiseled specimens, the corresponding values were 23.13 and 4.06. Does the true average strength appear to be different for the two methods of surface preparation? Test the relevant hypotheses using a significance level of .05. (Give ν to exact integer and t to 2 decimal places.)

ν	=
t (μwire - μhand)	=

Answer 1