Read what a graphic actually measures, then select the numbers that support the passage’s claim.
SAT40 min study guide8 indexed sections
BY THE END, YOU CAN
Read tables, bar graphs, and line graphs using titles, labels, legends, and units.
Compare levels, changes, differences, and proportions accurately.
Connect a numeric observation to a limited textual claim without inventing causes or trends.
BEFORE YOU START
Difference means subtraction; percent change uses the original value as its denominator.
A graph represents specified observations, not every possible case.
Original educational lesson. Work through the examples before revealing the practice answers. This lesson supports SAT Math and Reading and Writing skill study; it does not reproduce official questions or guarantee a score.
LEARN THROUGH ORIGINAL PRACTICE
Original SAT-style worked examples and practice
The teaching passages, worked examples and exercises in this lesson are original. They are not official College Board questions or past-exam reproductions. Blueprint and observed-practice analytics describe separate factual metadata; those source questions are not displayed here.
01 / UNDERSTAND & APPLY
Decode the graphic before judging the claim
Quantitative evidence combines reading comprehension with a table or graph. First identify the measured variable, population or categories, units, time period, and legend. Then state the claim in ordinary words: which quantity should be larger, smaller, increasing, or different? Finally choose the observation that matches both the graphic and that claim.
All data in this lesson are invented for teaching. They are not findings from an actual study. A correct number is not enough: an answer can quote a true value while failing to support the specific claim.
02 / UNDERSTAND & APPLY
Read tables by row and column
The table shows attendance at two fictional workshop sessions over three weeks. Each cell is a count of visits, not necessarily distinct people. A person attending twice contributes two visits. Read the row label and column label together before copying a number.
Comparisons within a week answer a different question from changes across weeks. In Week 2, evening exceeds morning by 15 visits; from Week 1 to Week 2, evening increases by 25 visits. Those are different subtractions.
Full-size scientific diagram. Swipe or scroll horizontally; keyboard users can focus the diagram and use arrow keys.
Invented data for reading practice. Rows identify weeks; columns identify sessions. One person can contribute more than one visit.
ORIGINAL WORKED EXAMPLE
A claim about a within-week comparison
Use the workshop table: Week 1 morning 40, evening 30; Week 2 morning 40, evening 55; Week 3 morning 50, evening 65. Which evidence supports “Evening attendance exceeded morning attendance in Week 2”? A 40 versus 30 in Week 1. B 55 versus 40 in Week 2. C 65 in Week 3. D Morning increased by 10 between Weeks 1 and 3.
Select the Week 2 row and compare the evening and morning cells.
55 is greater than 40 by 15. B gives the needed comparison.
A concerns another week and has the opposite direction; C provides only one cell from another week; D concerns change over time rather than sessions within Week 2.
Answer B. Week 2 evening had 55 visits and morning had 40.
03 / UNDERSTAND & APPLY
Read bars as quantities, not pictures
A bar’s endpoint encodes its value. The grouped bars below show the same fictional workshop data as the table. The legend identifies morning and evening; the vertical axis measures visits with a zero baseline and equal 10-visit intervals. Compare the bars within a group or the same color across groups according to the claim.
If another graph begins above zero, the visual height ratio can exaggerate a difference. Use labeled values rather than guessing from area or height. Error bars, when present, require the legend’s definition; overlapping bars alone do not license a statistical-significance claim.
Full-size scientific diagram. Swipe or scroll horizontally; keyboard users can focus the diagram and use arrow keys.
Same invented data as the table. Read the labeled endpoints; compare within a week or across weeks according to the claim.
ORIGINAL WORKED EXAMPLE
Absolute increase versus final size
Using the grouped bars, which supports “Evening attendance rose more than morning attendance from Week 1 to Week 3”? A Evening ended at 65. B Morning rose from 40 to 50 while evening rose from 30 to 65. C Morning was 40 in Week 2. D There were three weeks.
Compare changes, not just final values: 35 exceeds 10. B supplies both endpoints.
A may be true but lacks a baseline/comparison. C and D do not establish relative increases.
Answer B. Evening rose by 35 visits, versus 10 for morning.
04 / UNDERSTAND & APPLY
Read change along a line
The line graph shows an invented tank’s recorded water volume at the end of four days: 20, 35, 30, and 50 liters. A line joins successive observations; it does not establish every unmeasured value between them. An upward segment means an increase in the displayed quantity, and its steepness depends on the axis scales.
A higher point is a larger recorded amount; a steeper increase is a larger change per horizontal interval. Do not confuse the largest amount with the largest rise. Here the final amount is 50 liters and the largest observed one-day rise is 20 liters, from Day 3 to Day 4.
Full-size scientific diagram. Swipe or scroll horizontally; keyboard users can focus the diagram and use arrow keys.
Original fictional observations. Lines join measured endpoints; intermediate values and inflow/outflow are not separately measured.
ORIGINAL WORKED EXAMPLE
A qualified trend
Which statement is supported by the tank graph? A Volume increased on every recorded day. B Volume fell overall. C Volume rose overall but fell between Days 2 and 3. D Exactly 50 liters entered the tank on Day 4.
Compare first and last recorded amounts: 20 to 50 is a net rise.
Check intermediate steps: 35 to 30 is a decline, so the trend is not monotonic.
C captures both. A ignores the dip; B reverses the net change; D mistakes stored volume for inflow and ignores possible outflow.
Answer C. The net increase includes one observed decrease.
05 / UNDERSTAND & APPLY
Keep denominators and units attached
Counts and percentages answer different questions. A group can have more successful cases but a lower success rate if it has more total cases. To compare rates, divide successes by the matching group total. A change from 20% to 30% is 10 percentage points and a 50% relative increase; these are not interchangeable.
Read units before computing. A column labeled “thousands of visits” converts 4.2 to 4,200 visits, not 4.2 people. A chart of average duration does not reveal the total duration without the number of observations.
ORIGINAL WORKED EXAMPLE
More successes, lower success rate
Original fictional table: Method A repaired 18 of 20 devices; Method B repaired 24 of 40. Which supports “A had the higher success rate despite fewer repairs”? A A repaired 18 and B repaired 24. B A succeeded on 90% and B on 60%. C B handled 40 devices. D A and B repaired 42 devices altogether.
A’s rate is higher even though its successful count, 18, is smaller than 24.
B expresses the decisive rate comparison. A alone supports the count clause but not the rate clause; C and D do not compare rates.
Answer B. The success rates were 90% for A and 60% for B.
06 / UNDERSTAND & APPLY
Reject causes and extrapolations the display cannot show
A chart can document a difference without explaining it. If attendance rises after new posters appear, the graph alone cannot show that posters caused the rise. Weather, scheduling, or other changes may matter. Similarly, four observed days do not prove what will happen on a fifth day.
If an answer says “the data prove,” check whether its claim is merely a directly displayed numerical fact or a broader inference about causes, populations, or the future. For the latter, additional design or contextual evidence is needed.
ORIGINAL WORKED EXAMPLE
The chart does not isolate a cause
Original fictional scenario: A venue introduced posters between Weeks 1 and 2. Evening visits rose from 30 to 55. Which conclusion is justified by these numbers alone? A Posters caused every additional visit. B Evening visits increased by 25. C All residents saw the posters. D Visits will keep increasing by 25 each week.
Subtract 30 from 55 to get 25 additional visits.
B reports only the observed change.
A needs causal evidence, C needs exposure data, and D extrapolates a pattern beyond the observations.
Answer B. The observed increase was 25 visits; its cause is not established.
07 / UNDERSTAND & APPLY
Original practice: read the displayed data
Use the original workshop table/bar graph and tank line graph above. The data are also restated where needed for accessible reading.
ORIGINAL PRACTICE · 1
Workshop visits: Week 1 morning 40/evening 30; Week 2 40/55; Week 3 50/65. Which supports “Morning attendance was initially unchanged”? A Morning was 40 in both Weeks 1 and 2. B Evening was 30 in Week 1. C Morning reached 50 in Week 3. D Evening reached 65 in Week 3.
Reveal answer & reasoning
A
The claim concerns morning across the first two weeks, so the equal 40 values matter. B and D are another session; C is a later increase rather than the initial equality.
ORIGINAL PRACTICE · 2
Using the workshop data, which week had the largest combined session total? A Week 1, 70. B Week 2, 95. C Week 3, 115. D All weeks tied.
Reveal answer & reasoning
C
Totals are 40+30=70, 40+55=95, and 50+65=115. A and B give real totals but not the largest; D contradicts the unequal sums.
ORIGINAL PRACTICE · 3
Using workshop data, the evening-minus-morning gap was what in Week 3? A 115. B 15. C 35. D 25.
Reveal answer & reasoning
B
65−50=15. A adds the session counts; C is the evening increase from Week 1; D is the evening increase from Week 1 to Week 2.
ORIGINAL PRACTICE · 4
Tank volumes on Days 1–4 were 20, 35, 30, 50 liters. Which interval had a decrease? A Days 1–2. B Days 3–4. C Every interval. D Days 2–3.
Reveal answer & reasoning
D
35 falls to 30 only between Days 2 and 3. A and B are increases; C generalizes one decrease to all intervals.
08 / UNDERSTAND & APPLY
Original practice: match the numeric evidence to the claim
Check the population, denominator, measurement, and direction before choosing.
ORIGINAL PRACTICE · 1
Original fictional data: A program enrolled 80 people, 60 of whom finished; another enrolled 40, with 34 finishing. Which supports “The smaller program had a higher completion rate”? A 34/40=85%, versus 60/80=75%. B 60 is greater than 34. C 80 is twice 40. D 94 people finished in total.
Reveal answer & reasoning
A
The rate comparison in A addresses the claim. B compares successful counts; C only enrollment; D pools both programs and hides the comparison.
ORIGINAL PRACTICE · 2
Original fictional chart: The share choosing Route P rose from 20% to 30%. Which is the increase in percentage points? A 50. B 10. C 150. D 30.
Reveal answer & reasoning
B
30−20=10 percentage points. A is the relative percent increase, 10/20×100=50%; C expresses the final value as a percent of the initial value; D is the final share.
ORIGINAL PRACTICE · 3
A fictional graph labels its vertical axis “items, in thousands” and shows 2.5 for May. Which reading is correct? A 25 items. B 250 items. C 2,500 items. D 25,000 items.
Reveal answer & reasoning
C
2.5×1,000=2,500. A, B, and D use the wrong scale multiplier.
ORIGINAL PRACTICE · 4
Original fictional data show attendance increasing after a fee reduction, with no comparison group or other context. Best supported statement? A The fee reduction was the sole cause. B Every visitor attended because of the price. C Future attendance must rise. D Attendance was higher after the reduction; the data alone do not isolate why.
Reveal answer & reasoning
D
D separates the displayed sequence from an unestablished cause. A and B assign motives/causality; C extrapolates beyond observed data.
KEEP THE BIG IDEAS
Quick revision
Read title, axes, legend, units, and population before values.
Support the exact claim: level, change, comparison, and rate are different.
A count is not a percentage, and a stored amount is not a flow.
Graphs can show associations and changes without establishing causes.
The teaching notes, passages, worked explanations and practice are original. Official references identify the assessment framework and skill scope; they do not endorse this lesson or license official question reproduction.
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