Posts filed under: new SAT

Another Proving Grounds quiz coming your way. This one you should do without your calculator. Remember, Proving Grounds quizzes are available to everyone for one week, and then only available to Math Guide owners. Not a Math Guide owner yet? Got $20? :)…

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Time for another Proving Grounds installment, folks. Remember, these quizzes are available for one week for everybody, and then they’re for Math Guide owners only. “How can I get to be a Math Guide owner?” you ask?! Well, either you buy one right from me, or you forward me your receipt from some place like…

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Here’s the second installment of the Proving Grounds quizzes, which are available for everyone to try for one week before they become exclusive to Math Guide owners. A little parabola-heavy this week, but then again, who doesn’t love parabolas? Good luck! Mechanical Calculators image By Ezrdr (Own work) [CC BY-SA 3.0], via Wikimedia Commons…

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Below is the first in a series of tough quizzes for the new SAT that will be available to everyone for a week, and then only available to Math Guide owners. If you want access to all these quizzes long term, well, you might want to grab a Math Guide. They’re on sale now, and…

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I never did a post for this survey at the time—just promoted it on social media. However, for posterity, here’s what we learned about the March SAT—the first of the new format—when it happened.

March_2016_SAT_Difficulty_-_Google_Forms_2

I’ve received a few questions in my email asking about the Beta I’m running (full info here). Specifically, people want to know what they get if they sign up.

I figured that the best way to answer that question is just to post one of the chapters up here in public. If you join the Beta, you get access to chapters of the new book as I finish them just like you’ll see below. You also get the opportunity to, if you spot a typo, submit it to me in exchange for a $5 gift card.

Registered Math Guide owners can already access the Beta for free. For everyone else, it’s $16.99. When the actual book is released, paying Beta customers will be able to buy it at a big discount.

Update 2/7/16: Thanks to everyone who joined! The Beta is still running for existing members, but is now closed to new signups as I finish out the book. Original post below…


 

As many of you know, I’ve been working for some time now on putting together a Math Guide for the new SAT. It’s been slower going than I’d hoped, but I am making progress despite the fact that this is in many ways a ground-up rewrite.

I’m at a place now where I’m keen to start sharing some things and getting feedback from you guys. So, today I’m officially launching the Beta program, through which you’ll be able to read the book as I continue to write it.

Here are the important details.

  • Once you’re in the Beta, you can read the chapters I’ve uploaded in your browser. (You cannot print or download them.)
  • The Beta will officially end on March 5, the first day the new SAT is given. When the Beta ends, Beta memberships will convert to Math Guide owner memberships.
  • When the physical book is finally available for sale, everyone who paid for Beta access will receive a code to purchase the book at a discount.
  • If you spot a typo and report it to me (a misspelling, a missing negative sign, a grammar mistake) I will reward you with a $5 Amazon gift card. There is no limit to how many of these you can get. If you spot 10 errors, you’ll end up with $50 in gift cards.
  • Access to the Beta costs $16.99 USD. Sign up here by selecting the bottom option, or use the button below. (If you’re already a registered owner of the current Math Guide, though, you get it for free. You do not need to sign up, just go to the Math Guide Owners Area and look for the link.)

At the time I’m writing this (11/21/15), there are 13 chapters available, plus solutions to all the drills in those chapters. By the end of this week, I expect there will be 14 or 15 chapters available. After that, well, I am just going to keep working until it’s done. Come along for the ride!

keep-calm-and-randomize-on-1The new SAT will occasionally ask you questions about experimental design—whether the results of an study conducted by some students, for example, can be generalized to an entire population, or whether some experimental intervention has a causal impact. These questions will not be rocket science, and will not require any math at all, even though they’re in the math section. They will require some critical thinking and careful reading, though.

Randomization

They will also require you to be on the lookout for randomization. Generally speaking, the more randomized an experiment is, the stronger the conclusions that can be drawn.

If you’re doing research, and you want to be able to generalize your findings over an entire population, then you have to randomly select the subjects for your experiment from that entire population. Say you want to know, on average, how likely a new driver in the United States is to have an accident within one year of getting his or her driver license. If you want to be able to generalize your findings to the entire population of new drivers in the United States, then you need to do a random selection from that whole population. That’s not going to be easy to do, of course, but good research is hard! If you want to generalize about all new drivers in the US, you’re going to have to find someone who has the data you need. Maybe start calling the Department of Motor Vehicles in every state, or car insurance companies.

If you tried to take the easy way out and just went to your local shopping mall and asked the first hundred 17-year-olds you saw whether they’d been in an accident in the first year of having their licenses, then you could really only generalize your findings about the population of new drivers who visit that mall. Maybe going to that mall requires driving on a highway, which not every new driver in the country does. Maybe that mall is in a city, where people are more likely to get into a fender bender than new drivers who live in rural areas. Maybe people who shop in malls are more likely to get into car accidents than people who do most of their shopping online. You see?

Things get a bit more complicated when you’re dealing with experiments in which an intervention of some kind occurs. If you want to be able to generalize your results to an entire population, you need to select randomly from that population. If, further, you want to be able to argue that some intervention is causing some difference between experimental groups, you need to make sure that the intervention is assigned to subjects randomly. Again, in practice, this is not easy to do. That’s why good research is valuable: it’s hard to do!

Say a cognitive scientist is trying to determine whether a certain intervention can be used to cause infants to exhibit object permanence earlier than they usually do. Say, further, that this researcher managed to obtain a truly random sample of infants (this is very difficult, since parents would need to sign off on such a thing, and maybe there’s some difference between children of parents who would sign off and children of parents who wouldn’t…). If the data shows that babies who received the intervention did, on average, exhibit object permanence earlier than those who did not receive the intervention, the cognitive scientist could only claim that the intervention caused the accelerated object permanence if the babies given the intervention were selected at random.

Holy cow—that’s a lot of text about this stuff! My longwindedness notwithstanding, though, experimental design questions really aren’t hard—I promise. Just remember: if the question you get asks you to find a weakness in the design of an experiment, chances are very good that the answer will be something that’s obviously not random.

Other elements of experimental design

Remember that we use statistics to make generalizations about large populations based on observations we make of small groups from those populations. The small groups we use (randomly, if we’re doing it right) are called samples. The number of members of the sample is called the sample size. Generally speaking, the bigger the sample size, the more likely it is that it’s representative of the whole population.

Experimental design and interpretation questions on the SAT will usually provide a sample size. In the released tests, there’s no question where a too-small sample size is an experimental design problem, but I suppose it’s possible that something like that could appear in the future. Rule of thumb: if your sample size is bigger than 100, it’s probably fine. Only consider sample size a problem if it’s comically small.

This kind of question will also sometimes make mention of a study’s margin of error or confidence interval. If you’ve taken a statistics course, then you’ve probably had to calculate these things. You’ll never have to do that on the SAT. You’ll just have to know, in the most basic sense, what they are and why they’re important.

When we generalize what we’ve observed in a sample to draw a conclusion about an entire population, we have to remember that there’s a small possibility that we’re wrong. For example, after measuring the heights of 300 randomly selected 33-year-old American males, we might say that we are 95% sure that the true average height height of 33-year-old American males is within 3 inches of the 70 inch average we found. 3 inches is our margin of error, 67 to 73 is our confidence interval. As our sample size increases and we become more confident that the sample is representative of the population, our margin of error and confidence interval will shrink: we’ll be able to, with the same level of certainty, that the average we’re finding is closer and closer to the true population average.

One more thing: the 95% in this example is called the confidence level—you’ll probably only ever see confidence levels of 95% (maybe 99% once in a while). We include a confidence level to acknowledge that, even if we’ve designed our study carefully—randomized properly, made sure our sample size was sufficient, etc.—it’s mathematically possible that our sample just won’t represent the overall population well.

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As I said in my last post, I’m busy working on the new edition of the Math Guide for the new SAT. Here’s another quick pair of graph questions for you to try out.

You don’t need to be a site member to take this little quiz, but I’d encourage it. Site membership is free, and if you’re logged in all the quizzes you take will be stored. If you take enough of them, that adds up to useful data for you to see where your strengths and weaknesses are.

The next two questions refer to the following information.

hair salon website visitors

The owner of a hair salon is able to use his website’s analytics feature to track roughly how far visitors are from his hair salon, and how long those visitors stay on the website. Above is a scatterplot the salon owner made of the first 40 visitors to his website on a particular Saturday, and the line of best fit for that data. (You can click the graph to see a bigger version in a new window.)

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I’m in full-on writing mode for the next edition of the Math Guide, which will of course be aimed at the new SAT that debuts March 2016 (and the new PSAT, which debuts in October of this year). The new test is pretty different, so it’ll be a major overhaul—some chapters in the current guide will go away, other chapters will be brand new. Obviously, that means lots of new questions to write.

To that end, I’ll be posting practice questions on the blog with some regularity over the next few months. This will hopefully benefit those of you who are already prepping for the new exam. Your feedback will also help me fine-tune the questions for clarity and difficulty. It’s a win-win!

Anyway—here’s a question pair for you to play with. You don’t need to be a site member to take this little quiz, but I’d encourage it. Site membership is free, and if you’re logged in all the quizzes you take will be stored. If you take enough of them, that adds up to useful data for you to see where your strengths and weaknesses are.

The next two questions refer to the following information.
average global temperature 2
The graph above shows the average global temperatures measured in degrees Celsius during the month of May over two 15 year periods, and their respective trend lines. (You can click the graph to see a bigger version in a new window.)

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Data source: GISTEMP Team, 2015: GISS Surface Temperature Analysis (GISTEMP). NASA Goddard Institute for Space Studies. Dataset accessed 2015-06-15 at http://data.giss.nasa.gov/gistemp/.

By Alex E. Proimos (http://www.flickr.com/photos/proimos/4199675334/) [CC BY 2.0], via Wikimedia Commons

 

Am I missing something here? To me, this falls somewhere between not-a-huge-deal and kinda-a-big-deal. Of course, the nature of the paper SAT has always enabled people willing to risk being caught cheating to keep thinking about a question after time is called and revisit it during the next section, but now what you have is a section where calculators are prohibited followed immediately by a section where calculators are allowed.

There are, by design, questions in the no calculator section that would be very easy with a calculator. For example, look at question #18 on page 36 of Practice Test 4:

That’s a bit tricky without a calculator, no? But it’s a 2-second problem if you graph it. The function is at 0 when x = 5. No factoring or tricky algebra necessary. This is one of the hardest questions in the no calculator section.

If they know they’ll have their calculators and be able to graph the equation just a few minutes later, some kids are going to memorize the equation (or just flip back to it surreptitiously) and graph it when they get their calculators.

What boggles my mind about this issue is that it goes away if the calculator section comes first. I have to assume it wasn’t just a random choice to put the sections in the order they’re in, but I can’t imagine why this particular decision was made.

 

Hello Mike, I want to know about the new SAT of 2016. I am in high school and will be giving the SAT in 2016. Is there any thing(except without calculator section) or topic of math section that is new and can I start practicing for the new SAT now? And is new “writing” section like improving paragraph questions. I want to go for a good university or an ivy, do you recommend giving the essay section?

Thanks.

Yes, there’s a lot that’s new with the new SAT math—some of it is just different flavors (more algebra, less geometry) and some of it is totally new content (basic trigonometry, complex numbers).

College Board recently released 4 practice tests. You can download them here. You can also take them online at Khan Academy, but since you’ll take the real thing on paper, you might as well practice as you’ll play.

Impossible to say for sure about the Essay section yet, but I’m betting that the most selective schools will expect you to do it. If you’ve got Ivy aspirations, you should plan for that.

This kind of thing is going to be featured much more heavily on the new SAT than it is on the current one, so I figured I’d put a quick quiz together.

Struggling with any of these? Discuss them in the comments!

For each of the items below, choose the mathematical statement that is equivalent to the given sentence.

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Even though very little information has been released to date—not even a full practice test yet!—I’m hard at work trying to get a head start on the next iteration of the Math Guide for the new SAT (coming about a year from now—March 2016). When I write questions, I have a very hard time keeping them to myself, so if you’re curious what I’m thinking some of the tougher topics the new SAT might throw at you will look like, well, they might look something like this.

(Once you’re done here, you can try my last set of questions in the style of the new SAT.)

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How’s everyone else doing on this quiz?

7% got 5 right
13% got 4 right
18% got 3 right
26% got 2 right
24% got 1 right
12% got 0 right