How Do I Calculate Confidence Intervals for Two Means?

[girlwhoneedsmathhelp]

Here is the question I'm struggling with (Q1) :

I just... I just don't understand what my first step is.
Whats my barx1 and barx2? (bar x = mean, x1 = subscript 1)

My thoughts on approaching this question :
barX1 - barX2 `~ N(u1-u2, sd1^2/n1 + sd2^2/n2)
Find Z value when p = 0.975, z = + or - 1.96
Formula : (barx1-barx2)-z(root (sd1^2/n1 + sd2^2/n2) < (u1-u2) < (barx1-barx2)-z(root (sd1^2/n1 + sd2^2/n2)

Please help me! Thank you :)

 

[hutchphd]

In this case I believe the author wants you to look at the differences directly...the random variable is $(x_2-x_1)$ and the table provides the data. Maybe draw a graph.