Sounds like you'll be using an independent samples t-test or a 1 way between subjects anova, both are similar in this case because they're only 2 groups of comparison.
Color n mean s
blue 71 81.00 20.81
green 79 79.84 17.82
The T-Test Formula is:
(i) t = M1 - M2 / S(M1 - M2)
(ii) S(M1-M2) = Square root of (pooled variance / n1 + pooled variance /n2)
(iii) Pooled Variance = SS1 + SS2/ df1 + df2
so I guess you're having a hard time finding the SS for each group. It's as follows:
SS = DF * Variance
-the DF for the Blue Group is just n-1, so it's 71-1 = 70.
-the variance for the Blue Group is just the standard deviation squared, so it's 432.64
Now use the Formula SS = DF * Variance
The SS for the Blue Group is then 70*432.64 =30284.8
Now, repeat these steps and find the SS for the Green Group. When you have both of those, goto step (iii) in the formulas. Make sure you use the individual DF for each groups in this computation. After you calculate the pooled variance, you can now substitute it into part (ii). Once you calculated part (ii), you can finally complete the test.