I just took the survey too. I agree with gfweb's and Deryn's sentiment, regretfully. I selected "other" in many of your survey questions, in fact, so I could say "all of the above, depends on the circumstance and what I'm cooking" and variations thereof.
But to answer your question above in your OP - in a nutshell, in my case I find it is the preparation of ingredients that is the most time consuming more often than not. In many cases the actual cooking is done very quickly. (and even with stews or braises the "active time" often still is the larger chunk of time taken; the time the dish takes to cook is very largely "unattended" time)
I am not counting the time I spend on going around and buying groceries, true - that varies depending on how fancy I want my shopping trip to be. Depending on your target audience that may be a BIG factor for some folks.
I think it would be helpful if you delineated better what your target audience is and what sort of "cooking" you have in mind. (presumably general Western-type/European cooking? And not other cuisines?)¶¶ What sort of kitchen/basic utensils do you expect your target audience to have?
Many people "out there" eat fast food. Some more than others. Most folks here on eGullet tend not to do so, but (following on from Deryn's comments above) I imagine you must have realized that from browsing around here. (You have, right?) Are you targeting the proverbial "lower poorer working classes in urban USAmerican cities"? Living in areas characterized by some studies as those with no full-service groceries around? Or maybe not? Also, what do you mean by "fast food"¶¶? Folks with more disposable income also might eat a lot of "fast food", just maybe more pricey than simply McD's or Wendy's etc - like takeout from a gourmet store, or very fresh sushi-to-go (yes, there is such a thing) from various places, and so on. The choices available would also vary by urban/suburban/rural locale I would imagine.)
¶¶ ETA: Here's a useful quick reminder of your needing to specify what you mean by "fast food" and where and which cuisine. :-)