Lab experiments help the research isolate just the relations…

Lab experiments help the research isolate just the relationship between the independent and dependent variable while removing other possible explanation and are thus high in __________, but the results may not generalize to the real world and can thus be low in ___________. 

Mars candy bars tested a new package design using a test mar…

Mars candy bars tested a new package design using a test market and a control market. The data the experiment appears below showing the number of units sold in each market: Random Assignment Sales (November) Treatment (December) Sales (December 31) Treatment Market R — New packaging 1200 Control Market R — Existing packaging 800 For this data, the treatment effect equals: