Q6 - Four randomly chosen market

[agersh144]

I got this question wrong I choose D and the answer is E.

We are asked here to explain the reason for the 3rd city disparity between the 4 randomly choosen research groups who projected similar numbers for the relatively stable populations.

Let's hit the answers:

A) Uniformity would only exacerbate the paradox if it were more uniform that would make their job a heck of lot easier to project than its rapidly growing number currently do, as such it does not explain but only makes worse the dilemma.
B) High birth rate is not going to change the population projections over the course of the next 5 years (last time I checked 5 year olds don't typically reproduce). If the projections were 25 years in the future than this answer may perhaps warrant a second look, as is it's a pass.
C)Lower average age woopdy-doo, how does that explain why the companies can't project 5 years in the future?
D) Only second glance this explanation doesn't help as much as I had initiatially thought. It basically says the current population was taken into account then the estimates added on. But how does that explain why they varied so greatly? It doesn't. It simply says ok the population is 20,000 people we all took that 20,000 people and then added our 5 year estimates. How does that help us?
E) Ah here we go. The companies used the same method for the other two cities and got the same result. They used different method on this rapidly growing city and got a different result. That does in fact explain why the projections varied, we have a winner!

Hope this helps!

[tommywallach]

Hey agersh,

Great work. A few quick things to add:

(B) Your point here is totally solid, but it's not really relevant. (B) is giving us a reason why the population is going up, but we don't care why it's going up. We care why it can't be predicted!

(D) This is actually similar to (B). It tells us how the estimate was made in the rapid-growth city. Great. But because we don't know how estimates were made in the other cities, this doesn't tell us much. If the estimates were made in very different ways, that might explain the variation, but we don't know from this.

(E) This is right for the exact reason that (D) is wrong; it gives us different estimate methodologies.

Great work!

-t