Question: The following data represents the heat-producing capacity (in millions of calories per ton) of coal from a random sample of two mines:

Mine 1: 8380 8180 8500 7840 7990

Mine 2: 7660 7510 7910 8070 7790

Test whether the difference between the means of these two samples is statistically significant at level of significance α = 0.05 assuming that both populations are normally distributed, and state your conclusion.