The advanced technology of ski boots and bindings has brought a dramatic drop in the incidence of injuries that occur...

Irina on September 7, 2019

@Julie,

Let's look at the argument.

The advances in ski boot technology have brought a dramatic drop in slope injuries.
As a result, non-slope injuries increased from 10% of all injuries to 25%.

The stimulus is tricky because it represents the same set of facts using different statistical measures. The first premise tells us that the frequency of slope related injuries has declined from 9 per 1000 to 9 per 3000, but the frequency number alone tells us nothing about the total number of injuries at the resort or the ratio of slope v. non-slope injuries. The second set of statistics tell us that non-slope injuries increased from 10% of all injuries to 25%. This tells us that slope injuries constituted 90% of all injuries in 1950 and 75% in 1980. Since this is the only inference that must be true based on the facts in the stimulus, the answer choice (E) is correct. Note that (E) is not saying that the total number of injuries increased or decreased, only that the ratio of the slope to non-slope injuries has changed.

Does this make sense?

Let me know if you have any further questions.