Study guide
3.7 Statistics and Data Interpretation
ATI TEAS 7 Nursing Admission
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1 Introduction to the ATI TEAS 7
1.1 About the ATI TEAS 7 Exam 1.2 Content Area Breakdown 1.3 Scoring and Program Requirements 1.4 Building Your TEAS Study Plan
2 Reading
2.1 Identifying the Main Idea 2.2 Making Inferences and Drawing Conclusions 2.3 Summarizing and Paraphrasing 2.4 Understanding Text Structure 2.5 Author's Purpose, Tone, and Point of View 2.6 Evaluating Arguments, Evidence, and Credibility 2.7 Integrating Information and Interpreting Graphics 2.8 TEAS Reading Strategies, Pacing, and Practice
3 Mathematics
3.1 Whole Numbers and Basic Operations 3.2 Fractions 3.3 Decimals and Percentages 3.4 Ratios and Proportions 3.5 Algebra and Equations 3.6 Measurement and Unit Conversions 3.7 Statistics and Data Interpretation 3.8 Geometry Basics
4 Science
4.1 The Cardiovascular System 4.2 The Respiratory System 4.3 The Digestive System 4.4 The Nervous System 4.5 The Musculoskeletal System 4.6 The Urinary and Reproductive Systems 4.7 Cell Biology and Genetics 4.8 Chemistry Basics 4.9 Scientific Reasoning and the Scientific Method
5 English & Language Usage
5.1 Grammar and the Parts of Speech 5.2 Sentence Structure 5.3 Punctuation 5.4 Spelling and Word Usage 5.5 Vocabulary in Context and Word Parts 5.6 Paragraph Organization and the Writing Process 5.7 Formal vs. Informal Language, Audience, and Tone 5.8 TEAS English Section Strategies and Pacing
3.7 Statistics and Data Interpretation
Key Takeaways Explain This Topic AI
Mean = sum of values ÷ count; Median = the middle value after ordering; Mode = the most frequent value
For an even-sized data set, the median is the average of the two middle numbers
Range = Maximum value - Minimum value; it measures how spread out the data is
Read graph parts first: title, axis labels, and scale prevent misreading bar, line, pie, and scatter plots
- Correlation (two variables moving together) does NOT prove causation (one causing the other)
- Last updated: October 2026
Why Data Skills Matter
In the TEAS Measurement and Data area you both calculate simple statistics and read information from tables and graphs. Nurses interpret data constantly — trending vital signs, comparing lab values, reading the charts in research articles — so the exam checks whether numbers and pictures translate into correct conclusions. These items go quickly if you know the four core measures and slow down long enough to read every label on a graph.
Measures of Central Tendency
Central tendency describes the "middle" or typical value of a data set. Three measures appear on the TEAS.
- Measure Definition How to Calculate
- Mean The arithmetic average Sum of all values ÷ number of values
- Median The middle value The middle number once the data is ordered
- Mode The most common value The value that appears most often
Worked Example: For the data set 3, 5, 7, 7, 9, 10, 12 :
- Mean: (3+5+7+7+9+10+12) ÷ 7 = 53 ÷ 7 ≈ 7.57
- Median: the 4th of 7 ordered values → 7
- Mode: 7 (it appears twice)
- Finding the Median Correctly
The number-one median mistake is forgetting to order the data first . After ordering:
Odd number of values → the single middle number is the median.
Even number of values → average the two middle numbers.
Example (even set): 4, 6, 8, 10 has two middle values, 6 and 8, so the median is (6 + 8) ÷ 2 = 7 .
Measures of Spread
Spread describes how scattered the data is. The TEAS focuses on the range , the simplest spread measure.
- Measure Definition How to Calculate
- Range Distance from lowest to highest Maximum - Minimum
- Outlier A value far from the rest Spotted by inspection; can distort the mean
Example: For 2, 4, 6, 8, 10 , the range is 10 - 2 = 8 . Note that a single extreme outlier pulls the mean toward it but leaves the median relatively stable — which is why median is often the better "typical value" for skewed data.
Reading Graphs and Charts
Each graph type answers a different question, and the TEAS expects you to pick the right reading strategy. Before computing anything, read the title , both axis labels , and the scale .
- Graph type Best for How to read it
- Bar graph Comparing categories Compare bar heights against the y-axis scale
- Line graph Showing change over time Follow the line's slope; up = increasing trend
- Pie (circle) chart Parts of a whole Each slice is a percent of 100%; all slices sum to 100%
- Scatter plot Relationship between two variables Look at the overall direction of the cloud of points
- Frequency table Counts per value/category Sum the frequency column for the total
Worked Example (reading a bar chart): A clinic records patient visits by weekday. Using the bar heights below, the busiest day is the tallest bar (Thursday, 50 visits) and the total for the work week is 30 + 45 + 40 + 50 + 35 = 200 visits. The mean visits per day is 200 ÷ 5 = 40 , and the range is 50 - 30 = 20 .
Data Trends
A trend is the general direction data moves. On a line graph an upward slope is an increasing trend, a downward slope is decreasing , and a flat line shows no change. Always describe the trend in the variables' own terms ("heart rate rose steadily over six hours"), not just "the line went up."
Correlation Direction
On a scatter plot the cloud of points reveals a relationship called correlation :
Positive correlation: points trend up from left to right — both variables increase together (e.g., study hours and test scores).
Negative correlation: points trend down from left to right — one variable rises as the other falls (e.g., absences and grades).
No correlation: points show no pattern.
Correlation vs. Causation
This is a common reasoning trap. Correlation means two variables move together; causation means one variable actually produces the change in the other. A correlation does not prove causation, because a hidden third factor (a confounder) may drive both.
Real-World Example: Ice-cream sales and drowning deaths both rise in the same months, a strong positive correlation. Ice cream does not cause drowning — hot summer weather independently raises both. On the TEAS, choose answers that say a relationship was observed , not that one thing was proven to cause the other, unless a controlled experiment is described.
Recap
Compute the mean by summing and dividing, the median by ordering and taking the middle (averaging two middles for even sets), the mode by counting frequency, and the range by subtracting min from max. Read every label before interpreting bar, line, pie, and scatter graphs, describe trends in real-world terms, and never upgrade an observed correlation into a claim of causation.