TEAS measurement and data: reading graphs, choosing an average, converting units

The five objectives ATI lists

ATI's TEAS 7 content outline numbers them M.2.1 to M.2.5: interpret relevant information from tables, charts and graphs; evaluate the information in data sets, tables, charts and graphs using statistics; explain the relationship between two variables; calculate geometric quantities; and convert within and between standard and metric systems. The exam details page puts the math section at 38 questions in 57 minutes, 4 of them unscored, with numbers and algebra taking the other 18 scored items.

Two of those five already have their own guides here: geometry formulas sit in our TEAS math formulas guide and unit conversions in the conversions guide. This page covers the three data objectives, which are the ones applicants tend to skip because they look like common sense until a question asks for the median of an uneven list.

Read the graph before you calculate

The first data objective is mostly careful reading. Before looking at the answer options, read the title, both axis labels and the units, then check the scale: a bar chart whose vertical axis starts at 50 instead of 0 makes small differences look large. Then find the one row, bar or point the question is about. Many wrong options are the right calculation done on the neighboring column.

The same skill appears outside math. ATI's reading objectives include analyzing, interpreting and applying information from charts, graphs and other visuals, so time spent here pays off in two sections. When a question gives a table of values, copy only the numbers you need onto your scratch paper before doing any arithmetic, so a misread row is caught before it turns into a confident wrong answer.

Mean, median or mode: which one the question wants

ATI's help page on TEAS math lists statistics as mean, median, mode, range and standard deviation. The NIST statistics handbook defines the mean as the sum of the values divided by how many there are, the median as the value with half the data below it and half above, and the mode as the most frequent value. The range is the largest value minus the smallest.

The part a formula sheet will not teach you is when the three disagree. NIST notes that extreme values distort the mean but not the median, and that in skewed data the mean shifts toward the longer tail. Worked example: wait times of 2, 3, 3, 4 and 38 minutes. The mean is 50 divided by 5, which is 10. The median and mode are both 3. If a question asks which value best describes a typical wait, the median is the better answer, because one long wait pulled the mean far above every other value.

Watch for even counts. With six values the median is the average of the third and fourth once they are sorted, and forgetting to sort first is the most common way to get it wrong.

Explaining the relationship between two variables

This objective is usually a scatter plot or a two-column table. NIST describes the patterns to name: a positive relationship, where both values rise together; a negative one, where one rises as the other falls; and no relationship, where the points form a shapeless cloud. Some data curve rather than follow a straight line, and an answer that says the change is constant can be wrong for that reason alone.

The trap answer is a causal claim. NIST states that association does not imply causality, so a plot showing that patients who walk more have lower blood pressure supports a relationship, not proof that walking caused the drop. The TEAS science section tests the same idea under scientific reasoning, so learn it once and use it twice.

Sources

ATI: ATI TEAS Version 7 Content Outline. Measurement and data objectives M.2.1 to M.2.5 and the reading objective on charts, graphs and visuals

ATI: TEAS Exam Details. 38 math questions, 4 unscored, 57 minutes; 18 numbers and algebra and 16 measurement and data

ATI Help: Math Formulas to Know for the TEAS Exam. Statistics listed as mean, median, mode, range and standard deviation

NIST/SEMATECH e-Handbook of Statistical Methods: Measures of Location. Definitions of mean, median and mode; extreme values distort the mean but not the median; mean shifts toward the tail in skewed data

NIST/SEMATECH e-Handbook of Statistical Methods: Scatter Plot. Positive, negative and no relationship patterns; association does not imply causality