Explanation for Question 11 From the Math (Calc) Section on the 2020 March Sat
So in number 11, we're given 25 data values. 2 And these 25 are shown to us in the frequency, 3 right? Because seven plus five plus three plus eight, 4 plus two, those all equal 25. 5 And so those 25 data values are within a number of those intervals. 6 Right? And so it says that the set is an integer between one in 7 50 inclusive. This inclusive just means that one in 50 are possible 8 numbers that could be in the dataset. And it tells us that the table 9 gives us the frequency of the data for each of the five intervals, 10 which we can see right here in this right-hand column. 11 And then it asks us, which of the following intervals contains exactly two fifths 12 of the values in the dataset. Right? 13 So to find this two fifths, first, we need to figure out what is 14 two fifths of the values in the dataset. 15 And we have a total of 25 values, 16 right? So if we want to find what two fifths of 25 is, 17 we simply mean need to do 25 times two over five, 18 which will be 50 over five, 19 which is 10, right? 20 And so if you look up in our answer choices, 21 here are not at our answer choices, but at the intervals we see that 22 none of them exactly have 10. 23 So there's going to have to be a combination of intervals here now possible 24 combinations that could equal 10, right? 25 That could include the seven and the three, 26 but this can't be an interval because they're separated. 27 Right? So if it was an interval, it would have had to be one 28 to 30, but that would include this five so that one's not going to 29 work. Another possibility that's perhaps better is these last two here, 30 because eight plus two is in fact 10 and they're right next to each 31 other, which allows us to make it an interval. 32 So the interval that we're looking here looking for here is 31, 33 the low range of the lower interval to 50, 34 which is the higher end of the higher interval. 35 And we see that answer right here in answer choice D.