{"id":5652,"date":"2020-10-29t10:30:02","date_gmt":"2020-10-29t17:30:02","guid":{"rendered":"\/\/www.catharsisit.com\/hs\/?p=5652"},"modified":"2016-12-08t05:39:09","modified_gmt":"2016-12-08t13:39:09","slug":"sat-math-problem-solving-and-data-analysis","status":"publish","type":"post","link":"\/\/www.catharsisit.com\/hs\/sat\/sat-math-problem-solving-and-data-analysis\/","title":{"rendered":"sat math: problem solving and data analysis"},"content":{"rendered":"
<\/p>\n
covering 29% of the concepts on the sat, the problem solving and data analysis section is the second most common on sat math<\/a>, after heart of algebra. keeping in line with real-world scenarios, these sat problems will ask you to infer information based on a study with any number of participants or interpret data from a graph. this is actually beneficial for sat students, given that you\u2019ll be learning lots about cause and effect and inferential statistics in college.<\/p>\n now, let’s talk about how to approach the various types of problem solving and data analysis questions on the sat, plus some practice questions to get you started! feel free to use the table of contents to navigate directly to the topics you want to learn.<\/p>\n <\/a> <\/a> you can expect to see about 17 problem solving and data analysis<\/a> questions on the sat math section, although they will not be outright labeled by question type. some answers will be single-step questions, while others will be multistep problems. if you fear mental math, there’s no need to sweat it in this section—you’ll be allowed to use a calculator. like the other sat math sections, you’ll receive a problem solving and data analysis subscore on a scale of 1 to 15.<\/p>\n <\/a> <\/p>\n this problem solving and data analysis question type shouldn\u2019t come as a surprise since it has probably been part of your math courses for the last five years (yep, you most likely went over this stuff, in some form, all the way back in early middle school). i\u2019ll start with ratios.<\/p>\n a good way to think of ratios is apples and oranges. say i have two oranges and three apples, the ratio of oranges to apples is 2:3. seems straightforward. what if i have four apples and 6 oranges? if you answered 4:6, that is not quite correct. you have to think of the ratio the way you would a fraction, in lowest terms. both 4 and 6 can be divided by \u20182\u2019, giving you 2:3. notice how that is the same ratio as 2:3.<\/p>\n this highlights an important conceptual idea: ratio is not about total number<\/strong>. it is about the number of one thing, to the number of another thing, reduced, so that the ratio is expressed as two prime numbers.<\/p>\n one last thing about ratios. let\u2019s say you have a ratio of 1:2. this is not<\/u><\/strong> the same thing as \u00bd. the bottom number in a fraction is always the total. the total of a ratio is always the parts of a ratio added together. in this case, 1:2 is 1 + 2 = 3. so if i have 1 apple to two oranges, 1\/3 of the fruit are apples and 2\/3 are oranges.<\/p>\n if you have more than two ratios, make sure to add up all of the ratios. for instance, if the ratio of blue marbles to red marbles to green marbles is 2 : 5: 7, red\u00a0marbles account for 5\/14 of the total (2 + 5 + 7 = 14).<\/p>\n do you think you got that? well, here are some practice questions to test your knowledge of problem solving and data analysis.<\/p>\n percentages can be surprisingly complicated on the sat. part of that is because we can\u2019t always translate them into fractions, which are easier to work with algebraically. while it\u2019s easy enough to think of \\(50%\\) as \\(frac{1}{2}\\), it\u2019s rarely so easy to make the conversion on the sat, especially when the percentages given are, say, 35% or 15%.<\/p>\n finding a percent is pretty easy, as long as you have a calculator. just divide the part by the whole and multiply the decimal that comes out by 100.<\/strong> so if you ate 10 out of a serving of 12 buffalo wings, then you ate (10\/12)100=83.33%. remembering that formula can save you some grief when you have to use it algebraically.<\/p>\n however, the sat won\u2019t just test you on the simple process of finding the percentage of a number (like calculating a tip). instead, it\u2019ll ask you to calculate in reverse (finding the whole from the part), find a combination of percentages, find a percent change, or give some other scenario-specific piece of information.<\/p>\n being prepared for percent change questions, in particular, will take you far on problem solving and data analysis.<\/p>\n the equation for percent increase \\( = frac{text{new number – original number}}{text{original number}}*100 \\).<\/p>\n the equation for percent decrease is \\( = frac{text{original number – new number}}{text{original number}}*100 \\).<\/p>\n <\/a><\/p>\n a) 1 okay, this question is slightly evil, since shorts sounds like shirts and it is easy to get the two mixed up when you are reading fast. so always pay attention, even on easier questions!<\/p>\n since we know that kevin has 10 shirts and that 10, therefore, corresponds to the number \u20185\u2019 in the ratio, that the actual number of shorts, shirts, etc., he owns is double the number in the ratio. thus, he owns four shirts and six pairs of shoes. so he\u2019ll have to give away two pairs of shoes so that he\u2019ll have the same number of shoes as he does shorts. answer: (b). <\/p>\n on some questions, you\u2019ll have to figure out the proportion between two different units.<\/details>\n <\/p>\n a) 12,000 # of voters who voted in 2008 election is equal to 200,000 x 60 = 120,000<\/p>\n in 2010, the number of overall eligible voters increased by 20%, so 20% of 200,000 is 40,000 giving us 240,000 total voters.<\/p>\n 55% of 240,000 gives us 132,000. answer c).<\/details>\n <\/p>\n spr: ______________<\/li>\n<\/ol>\n we know that 7\/3 of mile = one inch.<\/p>\n we also know that the area is 49 square miles, meaning that each side = 7: \u221a49 = 7). to find how many inches correspond to 7 miles, we set up the following equation:<\/p>\n 7 = 7\/3x, x = 3<\/p>\n here is the little twist that you want to watch out for. the question is asking for square miles in inches, so we have to take 3^2 which equals 9.<\/details>\n <\/p>\n 5% = another possible question type, and one that most are familiar with and probably dread, is the percent question.<\/p>\n to reduce something by a certain percentage, either turn that percent into a ratio over 100 or convert the percent into a decimal by moving the point back two spaces. for example, 40% equals both 40\/100 and 0.40. so the answers are:<\/p>\n 5% = .05, 5\/100 or 1\/20 (you don\u2019t always have to reduce for quick calculations) <\/p>\n a) 4% when you are not given a specific value for a percent problem, use 100 since it is easiest to increase or decrease in terms of %.<\/p>\n 1st<\/sup> discount: 20% off of 100 = 80.<\/p>\n 2nd<\/sup> discount: 20% off of 80 = 64.<\/p>\n online, the coat sells for 40% off of the original department store price, which we assumed is 100.<\/p>\n online discount: 40% of 100 = 60.<\/p>\n this is the tricky part. we are not comparing the price difference (which would be 4 dollars) but how much percent less 60 (online price) is than 64 (department store sale price).<\/p>\n percent difference: (64 \u2013 60)\/64 = 1\/16 = 6.25%. answer b).<\/details>\n<\/div>\n <\/a><\/p>\n <\/a> <\/p>\n this is not an official title but the name i\u2019m giving to questions that deal with studies trying to determine cause and effect<\/strong>. <\/p>\n in order to understand how to approach subjects and treatments questions, let\u2019s talk about randomization. the idea of randomization is the essence, the beating heart, of determining cause and effect. it helps us more reliably answer the question of whether a certain form of treatment causes a predictable outcome in subjects.<\/p>\n randomization can happen at two levels. first off, when researchers select from the population in general, they have to make sure that they are not unknowingly selecting a certain type of person. say, for instance, that i want to know what percent of americans use instagram. if i walk on a college campus and ask students there, i\u2019m not taking a randomized sample of americans (think how different my response rate would be if i decide to poll the audience at a rolling stones concert).<\/p>\n on the other hand, if i went to a city phone directory and dropped a quarter on the page, choosing the name that the center of the quarter was closest to, i would be doing a much better job of randomizing (though, one would rightly argue, i\u2019d still be skewing to an older age-group, assuming that most young people have only cell phones, which aren\u2019t listed in city directories). for the sake of argument, let\u2019s say our phone directory method is able to randomly choose for all ages.<\/p>\n after throwing the quarter a total of a hundred times on randomly selected pages (we wouldn\u2019t want only people whose names begin with \u2018c\u2019, because they might share some common trait), our sample size consists of 100 subjects. if we were to ask them about their instagram use, our findings would far more likely skew with the general population. therefore, this method would allow us to make generalizations about the population at large.<\/p>\n which of the following is an appropriate conclusion?<\/strong><\/p>\n a) the exercise bike regimen led to the reduction of the varsity runners\u2019 time. when dealing with cause and effect in a study, or what the sat calls a treatment, researchers need to ensure that they randomly select amongst the participants. imagine that we wanted to test the effects on the immune system of a new caffeinated beverage. if researchers were to break our 100 subjects into under-40 and over-40, the results would not be reliable. <\/p>\n first off, young people are known to generally have stronger immune systems. therefore, once we have randomly selected a group for a study, we need to further ensure that, once in the study, researchers randomly break the subjects into two groups. in this case, those who drink the newfangled beverage and those who must make do with a placebo, or beverage that is not caffeinated.<\/p>\n at this point, we are likely to have a group that is both representative of the overall population<\/strong> and will allow us to draw reliable conclusions about cause and effect. <\/strong><\/p>\n another scenario and this will help us segue to the practice question above, are treatments\/trials in which the subjects are not randomly chosen. for instance, in the question about the runners, clearly, they are not representative of the population as a whole (i\u2019m sure many people would never dare peel themselves off their couches to something as daft as run three miles).<\/p>\n nonetheless, we can still determine cause and effect from a non-representative population (in this case runners) as long as those runners are randomly broken into two groups, exercise bike vs. usual one hour run. the problem with the study is the runner coach did not randomly assign runners but gave the slower runners one treatment. therefore, the observed results cannot be attributed to the bike regimen; they could likely result from the fact that the two groups are fundamentally different. think about it: a varsity runner is already the faster runner, one who is likely to improve faster at running a three-mile course than his or her junior varsity teammate. therefore, the answer is c).<\/strong><\/p>\n while d) might be true, and junior varsity subjects might<\/em> have become faster had they been in the bike group, it doesn\u2019t help us identify what was flawed about the treatment in the first place: the subjects were not randomly assigned.<\/details>\n<\/div>\n here are the key points regarding subjects and treatments (aka cause and effect questions) on sat problem solving and data analysis:<\/p>\n <\/a><\/p>\n <\/a> <\/p>\n the sat math test often asks you to do some statistics problems involving averages. finding the mean is the most commonly used average and, as it so happens, the most commonly tested when it comes to sat statistics. the formula is pretty simple:<\/p>\n {a+b+c+….}\/n<\/em> where n is the number of terms added in the numerator.\u00a0 in the set of numbers {2,3,4,5}, 3.5 would be the mean, because 2+3+4+5=14, and \\(14\/4=3.5\\)<\/p>\n if the numbers in a set are listed in order, the median is the middle number. in the set {1,5,130}, 5 is the median. in the set above, {2,3,4,5}, the median is 3.5, which is the mean of the middle two terms since there\u2019s an odd number of them.<\/p>\n the mode is just the number that shows up the most often. it\u2019s perfectly possible that there is no mode or that there are several modes. in the set {5,7,7,9,18,18}, both 7 and 18 are modes.<\/p>\n <\/a><\/p>\n <\/a> averages come up in algebra or word problems. you\u2019ll usually have to find some value using the formula for a mean, but it may not be as simple as finding the average of a few numbers.\u00a0 instead, you\u2019ll have to plug some numbers into the formula and then use a bit of algebra or logic to get at what\u2019s missing.<\/p>\n for example, you might see a question like this:<\/p>\n if the arithmetic mean of <\/i>x, 2<\/i>x, and 6<\/i>x is 126, what is the value of <\/i>x?<\/i><\/p>\n to solve the question, you\u2019ll need to plug it all into the formula and then do some variable manipulation.<\/p>\n \\(frac {x+2x+6x}{3}=126\\) medians and modes, on the other hand, don\u2019t show up all that often in problem solving and data analysis. definitely be sure that you can remember which is which, but expect questions on means, most of the time. as for other types of statistical analysis, you may also be asked to solve some problems involving standard deviation<\/a>.<\/p>\n if you\u2019re careful to remember that the question is asking you for the sum<\/i> of the sisters\u2019 ages, you can solve this one pretty quickly. keep in mind that we can\u2019t find their individual ages, though. there\u2019s not enough information for that. first we find the total combined age of the three, which must be 72, since \\(24*3=72\\). careful not to fall for the trap that is (e), we take the last step and subtract 16 from that total age to find the leftover sum, which is 56, or (c).<\/p>\n the phrase \u201cweighted average\u201d might be a little scary sounding, but it\u2019s nothing to get freaked out over. usually weighted averages on the sat will use the basic formula for finding the mean (link to \u201csat math types of averages\u201c). it’s pretty much the same skill. basically, weighted<\/i> means uneven,<\/i> here; the numbers that you\u2019re looking at don\u2019t carry the same importance. for example, if i\u2019m trying to find the average number of fleas that my pets have, and each cat has 150 while each dog has 200, then those two numbers have equal \u201cweight\u201d only if i have the same number of cats as dogs. let\u2019s say i have 1 of each.<\/p>\n \\(frac {150+200}{2}=175\\)<\/p>\n that\u2019s just a normal mean, so that\u2019s no problem. well, the fleas are a problem, i guess. and the fact that i\u2019m counting fleas<\/i> might have my family a little worried\u2026anyway, the math is easy. but that\u2019s a non-<\/i>weighted average.<\/p>\n for a weighted average, i would have a different number of cats than dogs. let\u2019s say i had 3 cats and 2 dogs. (and they all have fleas\u2026things are starting to get kinda gross. sorry.)<\/p>\n in order to give them the appropriate weight, we\u2019d have to multiply each piece appropriately and change the total (denominator) to reflect it.<\/p>\n \\(frac {3(150)+2(200)}{5}=170\\)<\/p>\n but if you expand that, you\u2019ll see that it\u2019s the same as the standard mean formula.<\/p>\n \\(frac {150+150+150+200+200}{5}=170\\)<\/p>\n just make sure you divide by five (because i have five pets) not two (for two types of pets).<\/p>\n <\/a><\/p>\n average rates are a type of weighted average. your sat problem solving and data analysis section will include a problem or two about these, and you need to be sure not to fall for the common trap.<\/p>\n maria\u2019s drive to the supermarket takes her 20 minutes, during which she averages a speed of 21 miles per hour. she takes the same route home, but it only takes 15 minutes to cover the equal distance. what was maria\u2019s average speed while driving?<\/i><\/p>\n this is a tricky, multi-step problem, and you can\u2019t plug in the answer choices to solve it,<\/a> sadly.<\/p>\n let\u2019s first find all<\/i> of our information, because the question has only given you part of it. you need to know the formula r=d\/t (rate = distance\/time)<\/strong>, also expressed as d=rt<\/strong> (easily remembered as the \u201cdirt\u201d formula). we\u2019re going to use it both ways.<\/p>\n using that formula, let\u2019s look at the first leg of her trip. she traveled for 1\/3 of an hour at 21 mph, so she must have traveled 7 miles.<\/p>\n that\u2019s \\(21*0.333=7\\)<\/p>\n using that info, we can figure out the rate of her trip back home. going 7 miles in 1\/4 of an hour on the way home, she went an average of 28 mph.<\/p>\n that\u2019s \\(7\/0.25=28\\)<\/p>\n so now we need to find the total <\/i>average. that\u2019s not the average of the two numbers we have! because each mile she traveled on the way there took more time than each mile on the way home, they have different weights!<\/p>\n \u2717 \\(frac{21+28}{2}=24.5\\)<\/p>\n instead, you need to take the total of each piece\u2014total time and total distance\u2014to find the total, average rate.<\/p>\n \u2713 \\(frac{14 text{ miles}}{.333 text{ hours} + .25 text{ hours}}=frac{14 text{ miles}}{.5833 text{ hours}}={24 text{ mph}}\\)<\/p>\n a) 55 miles per hour to figure out the average speed of the entire trip, divide the total distance by the total number of hours. the handy equation d = rt, where d is total distance, r is rate, and t is time, will make this easier.<\/p>\n d = 910, r = ?, t = 9 + 4 = 13 hours.<\/p>\n 910 = 13r, r = 70, answer c).<\/details>\n<\/div>\n i’ve never seen an sat problem solving and data analysis question that asks you to find an average based on percent weights (e.g. finding a final grade in a class where quizzes count for 70%, attendance for 20%, and participation for 10%). finding that<\/i> average is a little more complicated, so it\u2019s nice that we don\u2019t have to worry about it.<\/p>\n <\/a><\/p>\n <\/a> <\/p>\n among the math skills that sat problem solving and data analysis tests, reading data from tables or graphs is one of the more straightforward tasks. but there are a number of simple mistakes that might make you miss out on points if you\u2019re not careful. the best way to avoid those totally avoidable slip-ups is to train yourself to follow a pattern.<\/p>\n you\u2019ll want to read the headings, the axes, and the units of measurement, then make note of any missing information or obvious patterns.<\/p>\n after you\u2019ve done that, go ahead to the question.<\/li>\n for the easiest sat data questions, you\u2019re already finished\u2014they just want you to locate the info. but it might ask you to go another step.<\/li>\n a lot of sat prep has to do with training yourself against hasty mistakes, and tables and graphs are classic places to make those slips. follow the rules and you\u2019ll be much safer.<\/li>\n<\/ol>\n that’s all for the sat problem solving and data analysis section! we hope this breakdown was helpful for you. to read up on the other two sections of sat math, check out our posts on heart of algebra<\/a> and passport to advanced math<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":" learn how to approach different types of sat problem solving and data analysis questions, from statistics and percentages to graphs.<\/p>\n","protected":false},"author":10,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[91],"tags":[81],"ppma_author":[24882],"acf":[],"yoast_head":"\n
\n <\/p>\ntable of contents<\/h2>\n
\n
\n <\/p>\nquick facts about sat problem solving and data analysis<\/h2>\n
\n <\/p>\nratio, proportion, units, and percentage<\/h2>\n
understanding ratios<\/h3>\n
understanding percentages<\/h3>\n
practice questions<\/h3>\n
easy questions<\/h4>\n
\n
\nb) 2
\nc) 4
\nd) 5<\/p>\nshow answer and explanation<\/strong><\/summary>\n
medium difficulty question<\/h4>\n
\n
\nb) 120,000
\nc) 132,000
\nd) 176,000<\/p>\nshow answer and explanation<\/strong><\/summary>\n
difficult questions<\/h4>\n
\n
show answer and explanation<\/strong><\/summary>\n
\n
\n26% =
\n37.5% =
\n125% =\n<\/li>\n<\/ol>\nshow answer<\/strong><\/summary>\n
\n26% = .26, 26\/100 or 13\/50
\n37.5% = .375, 375\/1000 or 3\/8
\n125% = 1.25, 125\/100, 5\/4<\/p>\n<\/details>\n\n
\nb) 6.25%
\nc) 16%
\nd) 36%<\/p>\nshow answer and explanation<\/strong><\/summary>\n
\n <\/p>\nsubjects and treatments<\/h2>\n
subjects and treatments practice question<\/h3>\n
\nb) the exercise bike regimen would have helped the junior varsity team become faster.
\nc) no conclusion about cause and effect can be drawn because there might be fundamental differences between the way that varsity athletes respond to training in general and the way that junior varsity athletes respond.
\nd) no conclusion about cause and effect can be drawn because junior varsity athletes might have decreased their speed on the 3-mile course by more than 30 seconds had they completed the biking regimen.<\/p>\nshow practice question answer and explanation<\/strong><\/summary>\n
subjects and treatments: a summary<\/h3>\n
\n
\n <\/p>\nsat statistics (mean, median, and mode)<\/h2>\n
\n <\/p>\nwhat\u2019s important to know about averages on the sat?<\/h2>\n
\n
\n\\({x+2x+6x}=378\\)
\n
\n\\(9x = 378\\)
\n
\n\\(x=42\\)<\/p>\n
\nif three sisters have an average (arithmetic mean) age of 24, and the youngest sister is 16, what is the sum of the ages of the two older sisters?<\/i><\/p>\n\n
show answer and explanation<\/strong><\/summary>\n
\n<\/details>\n<\/div>\nwhat is a \u201cweighted average\u201d?<\/h3>\n
finding average rates<\/h3>\n
\n
average rate practice question<\/h3>\n
\nb) 65 miles per hour
\nc) 70 miles per hour
\nd) 75 miles per hour<\/p>\nshow answer and explanation<\/strong><\/summary>\n
weighted averages that you won\u2019t see on your sat<\/h3>\n
\nsimply put…<\/strong> if you\u2019re finding the average of two sets of information that already are averages in their own right, as the number of fleas per cat and the number fleas per dog, you can\u2019t just take the mean of those averages. you have to find the totals<\/i> and then plug them into the formula. you should be excited about these kinds of problems, if for nothing more than having the opportunity to bust out your handy-dandy, brand-spanking’ new sat calculator<\/a>. \ud83d\ude1b<\/p>\n
\n <\/p>\nsat graphs: tips and tricks<\/h2>\n
\n
\nit\u2019s tempting to jump right into the question, especially if you\u2019re feeling clock pressure.<\/a> but don\u2019t do it! usually, the question will make pretty much no sense if you don\u2019t have the context that the figure gives you. you\u2019ll end up reading the question, looking over the table\/graph, rereading the question, and then<\/i> finding the information you need. why waste the time doing it twice? scan the figure first.<\/p>\n
\nas is often true for other types of sat math problems, the written question might have some info in it that the figure doesn\u2019t include. just like you would write in angle measurements<\/a>, fill in any extra info; there\u2019s no reason to try to keep it in your head.<\/li>\n
\nyour sat might try to make the question more confusing by adding in a whole lot of superfluous information into the visual. check what the question asks for, then circle the area in the table or graph that answers the question (or gives you info that will lead to the answer).<\/p>\n
\nif you\u2019re asked about relationships between two things, look carefully at the relationships between 4-6 pieces of information (two x<\/i>s and two y<\/i>s), and write out the pattern. if you\u2019re looking for some variable, write out the equation. if it\u2019s not clear how to go about that, maybe you should try plugging answer choices in to see if they work.<\/li>\n
\nafter you\u2019ve done whatever math you need to, check your units. <\/i>it\u2019s easy to make a mistake by using minutes instead of hours, and the sat takes advantage of that in the incorrect answer choices.<\/p>\n