Explanation for Question 17 From the Math (Calc) Section on the 2020 March Sat
So looking at number 17, the most important thing that we need to know 2 right off the bat is that medians usually don't change. 3 When you add a new value in medians are very likely to stay the 4 same. Whereas a mean is extremely sensitive. 5 They're going to change a lot when you add in a new value, 6 so means like to change. 7 Now, if we know this information, which does get tested on the SAP relatively 8 often, um, then we should be able to eliminate answer choice a right, 9 because we know that the mean is not going to want to change. 10 Um, and we know we can also eliminate answer choice V right, 11 because we know that the mean will like to change. 12 So just to rephrase the median, doesn't like to change, 13 which is why a is wrong. We would not expect the median to decrease. 14 And also the mean, um, likes to change the mean is very sensitive. 15 And B says that it would remain the same. Um, 16 so now we just have to choose between D and C. 17 And so really, if you know this information, you don't have to do a 18 lot of math. You can make a very educated guess, 19 but just to show you that the median first is going to stay the 20 same, let's figure out what our median would be. When we have the 25 21 values only have the 26 values. 22 Now, if we have 25 values, then our middle value, 23 our 50th percentile value is going to be the 13th. 24 That's exactly in the middle. We look here, 25 four of our values are one and then seven of our values are two. 26 So four plus s...