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.
Place a piece of clean plywood gently over the newly installed tiles if you must walk on them before 24 hours has passed; the board will distribute your weight evenly and take pressure off of the tiles. 1  Plywood.  Avoid walking on the tiles with sharp heels as they may scratch the ceramic surface.