Write difference-yearly incomes of three geographical areas

Question

Random samples were selected from three populations. The data obtained are shown below.

Treatment 1  Treatment 2   Treatment 3

45                     30                 39

41                     34                 35

37                     35                 38

40                     40

42

At 95% confidence, test to see if there is a significant difference in the yearly incomes of the three geographical areas. Please note that the sample sizes are not equal.