Answer:
To find the value of the test statistic, we need to calculate the standard error of the difference between the means and then use it to calculate the z-score.
The formula for the standard error of the difference between the means is:
SE = sqrt((s1^2/n1) + (s2^2/n2))
where s1 and s2 are the sample standard deviations, and n1 and n2 are the sample sizes.
Substituting the given values, we get:
SE = sqrt((5^2/45) + (6^2/55)) = 1.257
The formula for the z-score is:
z = (x1 - x2) / SE
Substituting the given values, we get:
z = (25.5 - 22.6) / 1.257 = 2.31
Therefore, the value of the test statistic is 2.31