How to Solve Data Interpretation Questions

For Data Interpretation and Research Summaries questions on the ACT Science Test, you are often presented with a set of graphs and tables and required to answer relevant questions. It is important to take the time and thoroughly analyze the data before answering the questions.

Tips to Remember

1. Read all of the labels

What is in each column? What is in each row? What is the range of values? Does the data have a direct or indirect relationship? Do the lines have positive or negative slopes? Where was there the most change or growth? Where was there the least?

With this kind of discipline, you will understand what is being presented. The question becomes almost an afterthought, and you know exactly where to look for the correct information.

2. You won’t need all information to solve

Chances are the correct answer hinges on just one or two numbers from the data tables or graphs. Most ACT students get ACT Science questions involving data analysis wrong because they do not know what data to use to solve, not because the calculations involved is difficult. You will likely only be performing calculations as simple and easy as addition, subtraction, multiplication and division.

3. Round decimals and fractions

If the answer choices are very close together, then you need to be more accurate in your approximation. However, if the answer choices are markedly far apart, then by all means round to the nearest integer.

Practice Question

Two scientists are conducting experiments using a spectrum machine. The spectrum machine measures the transmittance and absorbance of solutions at various wavelengths of light. Scientists placed solutions of various chlorophyll concentrations into a spectrum machine and recorded the transmittance at 4 wavelengths in Figure 1.


According to the results of the experiment, chlorophyll has the highest transmittance at a wavelength of:

  1. 250 nm
  2. 350 nm
  3. 450 nm
  4. 550 nm


The values listed in Figure 1 for a transmittance of 250 nm - 73, 56, 40, and 29 - are the highest for each chlorophyll concentration. Therefore, figure 1 consistently shows the highest transmittance levels at a wavelength of 250 nm. The correct answer is A.