Autonomous investment is indicated by the intercept. 1  An Induced Slope: The slope of the investment equation (f) measures the change in investment resulting from a change in income. If income changes by $1, then investment changes by $f.
24 to 48 Hours. You should wait at least 24 hours before grouting the tiles. You may notice that the edges of the thinset or the thinset showing through the grout lines looks dry. Don't be fooled by this. The thinset under the tiles isn't receiving as much air as the edges and is therefor not fully cured.
Oil based polyurethane takes longer to dry than water based poly. 24 hrs before you can walk on the floors. Hours 24-48, you can walk on the floors with socks. Avoid shoes and bare feet. And, make sure your pets (who usually have bare feet) do not walk on the floors during this time. 48 hrs you can walk on it with shoes.