Explanation for Question 21 From the Math (Calc) Section on the Official Sat Practice Test 6
Question 21 reads a study was done on the weights of different types of 2 fish in a pond. So we're looking at different types of fish in a 3 pond. A random sample of fish were caught and marked in order to ensure 4 that none were weighed more than once. So none were weighed more than once 5 the sample contained to 150 large mouth bass of which 30% 6 weighed more than two pounds, which of the following conclusions is best supported by 7 the sample data. All right. 8 So let's read through the answer choices and see which one matches up best. 9 A, the majority of all fish in the pond weigh less than two pounds. 10 The reason that this answer is incorrect is because it refers to all fish 11 in the pond and the data that they're giving us only refers to 12 the large mouth bass. If it hadn't specified that if it said that the 13 sample contained 150 fish from the pond, 14 then we could assume that it was an indicative random sample, 15 but we're really only looking at large mouth bass for the data that they 16 give us B is incorrect for a similar reason. 17 It mentions all fish in the pond. Again, 18 moreover it mentions that only 30% of these large mouth bass weigh more than 19 two pounds. So we can't conclude that that's the average, 20 the average would be at, um, 21 at different point in the sample. Um, if only 30%, 22 way more, that's just a small subset and then see, 23 approximately 30% of all fish in the pond weigh more than two pounds. 24 This one is again incorrect because it references all fish. 25 And hopefully you're seeing a trend here D is going to be the right 26 answer because it says it references all large mouth bass. 27 And it says approximately 30% of all large mouth bass in the pond weigh 28 more than two pounds. And that is the best conclusion that you can draw 29 from that day.