Do I have this diagrammed correctly?
Economy doing badly --> real estate slump & car sales low
no real estate slump or car sales not low ---> economy not doing badly
No. You've essentially diagrammed that no real estate slump or car sales not low is sufficient to tell us the economy is not doing badly. But the language used in the stimulus is that either of those things is "consistent with" a healthy economy. But "consistent with" is not the same as "sufficient for." "Consistent with" doesn't tell us which way the arrows go.
For instance if I've got A --> B, I can say A is consistent with B, but I can also say that B is consistent with A (even though B is not sufficient for A).
So how do I know you've diagrammed it wrong? By the way the argument is set up. The last sentence says "Their occurrence together makes it quite probable that my conclusion
is correct. What's his conclusion? "The economy is doing badly."
Conclusions go on the right.
real estate slump & low car sales --> economy doing badly
economy not doing badly --> no real estate slump or car sales not low