Line graphs: the trend

Example 1

1. First, read the edges. The title says what is measured and when: the population of New York State, 1950 to 2020. The unit under the graph: people, in millions. The axis starts at 0 and has a line every 5 million.
2. A line graph shows change over time. Read it from left to right, one stretch at a time, and ask for each stretch: up, down, or flat?
3. 1950 to 1960: up (14.9 to 16.8). 1960 to 1970: up (to 18.2). 1970 to 1980: down, to 17.6. Then up at every step after that: 18.0, 19.0, 19.4, 20.1.
4. So the state grew in six of the seven decades and lost people in one, the 1970s. That is B.
5. A says “every decade,” but the line goes down from 1970 to 1980. C says most decades after 1970 were losses, but only one was.
6. D is about slope. The steeper the line, the faster the change. The steepest climb is the first stretch, 1950 to 1960 (about 2 million). From 2010 to 2020 the line rises less, about 0.7 million.
7. One more habit: a single dip does not change the overall trend. Over the whole graph, the state grew from about 14.9 to about 20.1 million.

Answer: B

Example 2

1. The question asks where the change was biggest, up or down. On a line graph that is the steepest stretch of the line.
2. Find each stretch’s change from the labels: 2019 to 2020, 40 to 45 (up 5). 2020 to 2021, 45 to 70 (up 25). 2021 to 2022, 70 to 75 (up 5). 2022 to 2023, 75 to 60 (down 15). 2023 to 2024, 60 to 55 (down 5).
3. The largest change is 25, from 2020 to 2021. On the graph it is also the steepest stretch. That is B.
4. C is a real fall, and a big one, 15 members, but it is less steep than the rise of 25.
5. A and D are gentle stretches of 5 members each.
6. Notice also where the line peaks: 2022, at 75 members. The peak is the highest point; the fastest change is the steepest stretch. They are different questions.

Answer: B