To find the median, we must first sort the data, and then find whatever is in the middle. This is common knowledge. But how do you sort 10 terms quickly? One idea is to pick a number and then count how many pieces of data are above it, and how many are below it. Then if we had 4 above and 6 below, we could easily adjust from there. Sorting all the data is really unnecessary; we merely need the middle, or middle 2 terms.
A quick scan of the Number of Theaters column shows us that some are above and some are below 4,000. Knowing the GRE, it's highly likely that a nice round number will divide the data cleanly in half. A quick count confirms this to be true; there are 5 movies above 4,000, and 5 below.
We can quickly determine the middle two pieces of data by finding the highest number in the 3,000s and the lowest number in the 4,000s: 3,792 and 4,028, respectively. In an even number of data points, the median is exactly midway between the middle two data points. The easiest way to find that is to simply average them. These two numbers are conveniently easy to add, getting us 7,820. Divide it in two to get the average, which is the median, which is 3,910, which is answer choice B.
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