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.
Bottom Line. The time required to wait before walking on a newly tiled floor varies depending on the adhesive and grout brands chosen, and if a sealant is used. Generally at least three days from the time the tile is laid should be allowed before using the floor.