In the United States, of the people who moved [CR]

please help!
exam in 3 days

The premises are:

1) In the United States, of the people who moved from one state to another when they retired, the percentage who retired to Florida has decreased by three percentage points over the past ten years.
2) Many local businesses in Florida cater to retirees

The conclusion is:

1) This decline is likely to have a noticeably negative economic effect on these businesses

This argument confuses percentages and numbers. The premises refer to the percentage of retires moving to Florida. The conclusion assumes that since the percentage decreased by 3 points the total number of retirees decreased and thus it is negative for business. This does not have to be the case. If the total number of retirees in the country increases, then Florida’s share in number may still go up even though their percentage went down. In other words, if the pie gets bigger your smaller share of the pie may still result in a bigger slice than you previously had.

Consider the following,

Before After
Nationwide Retirees 10,000 100,000
Florida’s Share 30% 27%

Total Number of
Retirees in Florida 3000 27,000

In this example, even though Florida’s share went down 3% the number of retirees increased substantially since the total number of retirees nationwide increased. Answer choice D refers to this. This clearly weakens the conclusion that the 3 percentage point decrease is bad for business.

Sorry I just saw your question regarding answer A. Answer A doesn't weaken the conclusion.

The conclusion is that the percentage point decrease in people retiring to Florida is likely to have a noticeably negative economic effect on business. Even if "Florida attracts more people who move from one state to another when they retire than does any other state", the total number of retirees living in Florida can still be less than it was than it was 10 years ago since their "market share" decreased by 3 points. (This would be true if the total number "market" of retirees stayed the same or went down.) If the number of retirees is lower then the conclusion that the percentage decrease is negative for business would hold.

Hope this helps...

much clearer, thank u
yes, i was battling between A & D

Wow. Great explanation. Thanks.