Two Random Samples from Two Normal Populations Produced the Following $\bar { X } _ { 1 }$

Essay

Two random samples from two normal populations produced the following statistics:
n1 = 51, $\bar { X } _ { 1 }$ = 35, s1 = 28.
n2 = 40, $\bar { X } _ { 2 }$ = 28, s2 = 10.
Assume that the two population variances are different. Estimate with 95% confidence the difference between the two population means.