<p>^In your link it explicitly states:</p>
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<p>Now if you look at the box following that paragraph this whole matter will be settled.
The answer is = 1/4.</p>
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<p>What were they asking for? (18-13)/(2002-1980)? I hope so.</p>
<p>God, I must sound paranoid right now, huh?</p>
<p>Yes. It had a slope of 5/22, which is closest to 1/4. Is that what you put?</p>
<p>I put 1/4.</p>
<p>I’m confused about what the question asks for. It essentially gives you a graph and asks for the “average rate of change” between two x-values? That’s in standard language just the slope (delta y / delta x). But I read one of your posts in the other thread and you said it was one of the last questions of its section, which implies it should be more complicated and difficult than that. How could that be? Are you sure your understanding of what the question asked for is correct?</p>
<p>well i did not have this question on my test. but if it asked for the average rate of change, and the graph wasn’t just a striaght line, but like a scatterplot connected in segments. what if u took the slope of each segment and averaged them out? Since that would be the average of the rates of change. idk it sounds pretty dumb but i didn’t really see the question so idk. but if its from 1980-2002, there would be 22 rates which would take a long time to average</p>
<p>^
But that’s not what they asked for. They just asked for the “average rate of change”, a term that is a synonym for “slope of the secant line which connects the two given end points”. Google it if you don’t believe me.</p>
<p>It’s usually asked for when the graph is (at least roughly) linear. </p>
<p>If they wanted the annual percent growth rate, first of all they would have ASKED for that and second of all, they would have used data that was (roughly) exponential. Otherwise, the annual growth rate would keep changing (decreasing in fact).</p>
<p>The answer is 1/4. No questions asked.</p>
<p>Can anyone confirm if this was the experimental section? I know that one of my math sections was experimental, and it could very likely be this one.</p>
<p>No, this section was not experimental.</p>
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<p>That’s the main question I have; I’m not quite sure what “average rate of change” means.</p>
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<p>Definitely not experimental. My experimental was writing with an Improving Paragraphs about CS Lewis and writing for children.</p>
<p>From [Mathwords:</a> Average Rate of Change](<a href=“http://www.mathwords.com/a/average_rate_change.htm]Mathwords:”>Mathwords: Average Rate of Change) –</p>
<p>Average Rate of Change</p>
<p>The change in the value of a quantity divided by the elapsed time. For a function, this is the change in the y-value divided by the change in the x-value for two distinct points on the graph. </p>
<p>Note: This is the same thing as the slope of the secant line that passes through the two points. </p>
<p>From [Introductory</a> Calculus: Average Rate of Change, Equations of Lines](<a href=“AlgebraLAB: StudyAids”>Introductory Calculus: Average Rate of Change, Equations of Lines)</p>
<p>AVERAGE RATE OF CHANGE AND SLOPES OF SECANT LINES: The average rate of change of a function f(x) over an interval between two points (a, f(a)) and (b, f(b)) is the slope of the secant line connecting the two points:</p>
<p>For example, to calculate the average rate of change between the points: </p>
<p>(0, -2) = (0, f(0)) and (3, 28) = (3, f(3))</p>
<p>where f(x) = 3x2 + x – 2 we would:</p>
<p>(f(3) - f(0))/(3-0) = (28 - -2)/3</p>
<p>This means that the average of all the slopes of lines tangent to the graph of f(x) between the points (0, –2) and (3, f(3)) is 10.</p>
<p>There are more sites out there with this info…</p>
<p>My question is why this question was placed toward the end of its math section. I don’t find “average rate of change” ambiguous or arbitrary at all, especially since the ratio/unit is given explicitly. In this context, a rate is a speed, like 5 miles per hour, not a percentage. A rate (of change) literally means a speed (of change), so I feel like there’s something else in the problem that you guys missed, unless the question was really that straightforward.</p>
<p>The reason it may have been placed towards the end because the graph went from 1980 to 2002, but it went every other year (or every few years). That may have people tripped people up.</p>
<p>Then again I found all the final 2-3 questions on that SAT not to be the most difficult. I do know sometimes will do #19 as a 5 and #20 as a 4. In my opinion this problem was probably a 4.</p>
<p>Out of curiosity, can anybody think of why 2 and 2.5 were given as possible answers?</p>
<p>@pckeller is completely correct. Rate of change does not have to be a percent, and the specification of the unit in the question removes any ambiguity (as well as the lack of percent signs in the answers). Having said that, I don’t think I’ve seen a rate of change question on the SAT before. At least, @pi, you seem to have gotten the correct answer anyway.</p>
<p>The only one I can remember is from the first BB. I went back and found it…
Test#6, section 3 (an 18 q section) #6…</p>
<p>It’s a graph of homes sold over a period of 5 years and they ask for the decrease per year over the last 3 years.</p>
<p>But I think the thing that makes the current question harder is that the quantity that is changing is itself a rate.</p>
<p>wow i completely screwed up this problem…lol, ended up getting an answer that was not a choice so i left it blank</p>
<p>experimental question i think …</p>
<p>^Definitely not experimental.</p>