<p>Barron’s covers both of these in their chapter about data analysis and stats, but do I need to know them for the test? I haven’t ever seen a question that required knowledge of either on the 2 Barron’s tests I’ve taken or the 3 Spark Notes’ tests.</p>
<p>for standard deviation. just look at the set and see how much the biggest # is bigger than the smaller one. Ex. Set with 1,1,2,3,3 has smaller SD than 1,1,20,40,40, </p>
<p>I THINK…
When i took it in January no questions on regression or SD.</p>
<p>Check out this</p>
<p><a href=“http://talk.collegeconfidential.com/sat-subject-tests-preparation/544092-complete-guide-sat-subject-tests-mathematics.html[/url]”>http://talk.collegeconfidential.com/sat-subject-tests-preparation/544092-complete-guide-sat-subject-tests-mathematics.html</a></p>
<p>Explains how to do regression and SD with your calculator so there’s no thought involved.</p>
<p>I’m not sure if it’s in the complete guide, but the easy way is to just punch the list into your calculator and do stat -> calc -> 1-variable stats. sigma-x (the one between Sx and n) is your standard deviation.</p>
<p>Going through old AP questions and taking practice exams, I’ve seen one or two free response questions on regression. I have yet to see anything about standard deviation.</p>
<p>AP questions???</p>
<p>Also does the test ever cover histograms, or boxplots?</p>
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<p>Not always true. You seem to be describing the range (difference between highest and lowest). </p>
<p>Consider the following sets: </p>
<p>S1 = {1, 5, 5, 5, 5, 5, 5, 9}
S2 = {1, 2, 3, 4, 5, 6, 7, 8} </p>
<p>According to your argument, S1 would have a higher standard deviation because the biggest number is bigger than the smallest number by a larger margin. </p>
<p>Standard deviation is a measure of variability, i.e. how “clustered” the data are around the mean (low SD) vs. how “spread out” the data are (high SD). </p>
<p>Computing the standard deviations (by hand or by calculator) will tell you that S2 has a larger standard deviation than S1. </p>
<p>@OP: I have never seen a SD question on the SATII (although it doesn’t hurt to know it!). IMO it is much likelier that you will see a question on (linear) regression than a question on standard deviation, although both are pretty unlikely. Never seen histograms or boxplots either, but those are really easy topics. Why not just learn them anyway?</p>
<p>Standard deviation DOES turn up on the Math II test, and I wouldn’t say rarely either. Understand how standard deviation is calculated. On the Jan 09 test, there was a standard deviation question that gave 5 lists and asked which one had the lowest standard deviation.</p>
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<p>I guess you should listen to Latency here (with emphasis on the word understand). Although I still think it didn’t show up, I took the test far too long ago ('07) to remember accurately. </p>
<p>Since magiscoder brought it up earlier, I thought it would be worth mentioning to make sure you don’t just use the calculator and get Sx confused with sigma_x. </p>
<p>Sx is the “sample standard deviation”. Basically, when you use a sample (subset) of a population to make an inference about the true standard deviation of the entire population, Sx takes into account an adjustment factor (although it’s not perfect per se). Known as Bessel’s correction, it involves dividing by “n-1” instead of “n” in the definition of standard deviation that you should know. </p>
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<p>That is so not the point. Mathematics is all about thought. Think about it like this: You are a bright young student wanting to go to college. Any idiot can be taught how to press some buttons on a calculator and get an answer right. What separates you from him/her?
Answer: intellectual curiosity</p>
<p>^ Yes, but your intellectual curiosity doesn’t count for anything on the test.</p>
<p>I just know how to make a list and then evaluate it’s SD using 2nd STAT - Math - stdDEV( </p>
<p>Is that all you need to know?</p>
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<p>I don’t know about you, but “standardized test” and “intellectual curiosity” seems somewhat oxymoronic.</p>
<p>Why are you guys so narrowly focused on a damn test score? It’s not just about the stupid test. You’re here doing exactly what the standardized testers want you to do. They don’t care if you learn or understand anything. That’s why we’re so conditioned to think that intellectual curiosity necessarily has to be mutually exclusive from standardized testing. </p>
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<p>Anyway, there’s really not much I or my examples can do to change your temperament. What I can do is ask you this: </p>
<p>Suppose there are two independent random variables, A and B. The standard deviation of A is 3, and the standard deviation of is B 4. What is the standard deviation of the random variable C and D, where C = A + B, and D = A - B? Use your calculator and answer me that.</p>
<p>A test is simply a means to an end. Just because you adopt an efficient strategy for achieving the highest possible score (thus increasing your admissions chances at any given college) you can doesn’t mean your life is defined by your approach to standardized tests. If you want to derive the formula for standard deviation and how to calculate it by hand, fine. But the SAT 2’s are not the place for it.</p>
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<p>IMO the fact that you didn’t do the (easy) problem really says something. </p>
<p>Anyway, I don’t want to turn this into a huge debate or anything. (I’m saying this because it looks like you followed me over to the AP physics thread…) Just offering my perspective/input to try to help the OP. Seems like you guys already have your minds made up, and I think it’s actually kinda sad. Oh well.</p>
<p>Standard deviation appeared three times on Math Level 2 in 2008 (one time with z-score); I did not know about Jan 2009 - thanks, Latency!
All you need for these questions is understanding of the concept and the formula.</p>
<p>I will take SAT II Math in May and resurrect this thread with my deviant report. :)</p>