In an attempt to compare the durability of two cements, X and Y, 10 pieces of type X and 14 pieces of type Y were tested. You are interested toknow if the means of X and Y are equal and you do not know anything about the population variance but you do assume that the population distributions are both normal. You obtain:

. x bar = 129.44

y bar = 122.65

sx = 9.15

sy = 11.02

What is the value of the test statistic you will use? Roundto the nearest tenth such as 23.4