GED Science Practice — Interpreting data and graphs
Average Triclosan Concentration in Urine
Tap any bar to see its value — graph stays visible on every tab
Data: National Institute of Environmental Health Sciences.
What is this question about?
Triclosan is an antimicrobial chemical found in many personal care products — hand soaps, toothpaste, and deodorants. Because it is absorbed through the skin, scientists have studied how much builds up in people's bodies.
The graph shows average triclosan concentrations measured in urine (µg/L) across seven age groups in the U.S. population.
The GED question asks:"Which statement is supported by the results in the graph?"
Key science vocabulary
µg/L
Micrograms per liter — how much triclosan is in urine. 1 µg = one millionth of a gram.
Bar chart
Shows one value per category. Taller bar = higher concentration.
Urinalysis
Testing urine to detect substances absorbed by the body.
Average
The typical value for a group — not every individual's level.
What skill does this test? Reading a bar graph, comparing values, and identifying which choice is actually supported by the data — not just plausible-sounding.
Average triclosan concentration in urine by age group
Tap any bar to see its exact value.
Data: National Institute of Environmental Health Sciences.
How to read this graph
X-axis
Age groups — who was tested. Seven groups from 6–11 through 60+.
Y-axis
Triclosan in µg/L. Higher number = more triclosan in the body.
Tallest bar
That age group has the highest average triclosan concentration.
Pattern?
Does it go up with age? Stay flat? Peak at one group?
Common mistake: GED graph questions include choices that sound reasonable but are NOT shown by the graph. Only choose what the graph directly supports.
Data table — all seven age groups
The highlighted row is the age group with the highest concentration.
Age group
Avg. (µg/L)
Rank
6–11 yrs
7
6th
12–19 yrs
14
3rd
20–29 yrs
18
2nd
30–39 yrs
20
1st (highest)
40–49 yrs
16
4th
50–59 yrs
9
5th
60+ yrs
7
6th
What patterns does the data show?
Concentration is NOT the same across groups — ranges from ~7 to ~20 µg/L
30–39 age group has the single highest average (~20 µg/L)
Concentration does NOT simply increase with age — it peaks at 30–39 then drops
Youngest (6–11) and oldest (60+) both have the lowest levels
There is no clear upward or downward trend across all groups
Critical thinking: The graph only shows concentrations by age group. It does NOT tell us WHY levels differ. We cannot assume higher concentration means more product use.
Breaking down each answer choice
WRONG
"Triclosan concentration does not vary significantly among different age groups." The graph shows variation from ~7 to ~20 µg/L — nearly a 3× difference. The data directly contradicts this.
WRONG
"Increased levels of triclosan in urine are related to increased age." Concentration peaks at 30–39 then FALLS in older groups. Ages 50–59 and 60+ are lower than 12–19. No simple age-increase pattern exists.
CORRECT
"Triclosan concentration in urine is highest in the 30- to 39-year-old age group." The 30–39 bar is the tallest (~20 µg/L). This is a direct, factual reading of the graph. No assumptions needed.
WRONG
"People aged 20–29 likely use more products containing triclosan." This requires assuming higher concentration = more product use. The graph only shows urine concentration, not product usage. Many other factors could explain the difference.
GED strategy for graph questions
Step 1: Read the title — what is the graph measuring?
Step 2: Read both axes — categories (X) and measurement (Y)?
Step 3: Identify highest, lowest, and any patterns
Step 4: For each choice ask: "Does the graph directly show this?"
Step 5: Eliminate choices that require assumptions or outside knowledge
Rule of thumb: The correct answer is always something you can point to directly in the data. If you need to guess WHY — that choice is probably wrong.
