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How to Solve Statistics Word Problems

The hardest part of most statistics word problems isn’t the math — it’s the translation. If you can turn the story into a clean “given/asked” setup, the calculations (mean, median, z-score, probability) become straightforward.

🧾 Statistics⏱️ ~20 min read🟡 Intermediate

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A Simple Translation Template

For almost any statistics word problem, start by writing this mini-template on your paper:

Given: (numbers, units, conditions)
Asked: (mean / median / probability / percentile / z / SD / compare)
Model: (dataset? normal distribution? sampling?)
Plan: (formula + steps)
Answer: (one sentence with units)

This prevents the most common error: doing a correct calculation for the wrong question.

Common Phrases (and What They Usually Mean)

Word problems often hide the math behind everyday language. Use this quick “dictionary” when you translate.

  • “average” → mean (unless the problem hints median because of outliers)
  • “typical” → mean or median (choose median if there are extreme values)
  • “most common” → mode
  • “spread / variability / consistency” → standard deviation or IQR
  • “unusual / how many standard deviations” → z-score
  • “probability / chance / likelihood” → probability rules or a distribution model
  • “assume normal” → use z-scores and areas under the curve

One underrated skill: decide whether you are working with a raw list of values (compute directly) or adistribution model (normal, binomial, etc.). The phrase “normally distributed” is a huge signal that you should switch from list-based calculations to z-scores/probabilities.

Step 1: Identify Which “Statistics Tool” the Problem Wants

Measures of center

Keywords: average, typical, middle, most common. Tools: mean, median, mode.

Measures of spread

Keywords: variability, consistency, spread. Tools: range, IQR, standard deviation.

Standardization

Keywords: how unusual, compare across tests, above/below average. Tools: z-score.

Probability / percentiles

Keywords: chance, likelihood, percentile, above/below, between. Tools: probability rules, normal CDF, z-table.

When a problem says “assume the distribution is normal,” that is a strong hint you’ll use z-scores and areas under the curve.

Example 1: Mean From a Story

Problem: A student studies for 2, 3, 4, 1, and 5 hours over 5 days. What is the average time studied per day?

The word “average” signals mean.

mean = (2 + 3 + 4 + 1 + 5) / 5
mean = 15 / 5 = 3

Answer: The student studied an average of 3 hours per day.

Example 2: Median (Odd vs Even)

Problem: The prices of 6 items are $8, $10, $10, $12, $100, and $120. Find the median price.

First, the list is already sorted. Because there are 6 values (even), the median is the average of the 3rd and 4th values.

median = (10 + 12) / 2 = 11

Interpretation: Half the prices are below $11 and half are above. Notice how the outliers ($100 and $120) do not affect the median much.

Example 3: Z-Score From Context

Problem: SAT scores are normally distributed with mean μ = 1050 and standard deviation σ = 200. A student scored 1450. How unusual is this score?

“How unusual” is code for a z-score.

z = (x − μ) / σ
z = (1450 − 1050) / 200 = 400 / 200 = 2

A z-score of 2 means the score is 2 standard deviations above the mean — definitely above average. If the question also asked for percentile, you would convert z = 2 into an area under the curve.

How to Interpret Standard Deviation in Words

Many word problems ask you to compare “which group is more consistent” or “which set has more variability.” That is a spread question. The most common spread measure in intro stats is standard deviation.

Rule of thumb: larger standard deviation → values are more spread out → less consistent. smaller standard deviation → values cluster closer to the mean → more consistent.

If you are given two groups with the same mean but different standard deviations, the group with the smaller standard deviation has more predictable results.

Example 4: Probability in a Word Problem

Problem: A multiple-choice quiz has 10 questions with 4 options each. If you guess on every question, what is the probability you get exactly 7 correct?

This is a probability model. Each question is a trial with probability p = 1/4 of being correct. The phrase “exactly 7 correct” hints at a binomial-style setup.

A full solution uses combinations to count how many ways to choose which 7 questions are correct, then multiplies by probabilities. If you want a reference that connects word problems to probability rules and counting ideas, the OpenStax section on probability and counting rules is a helpful companion.

Number of ways: C(10, 7)
Probability: C(10, 7) · (1/4)^7 · (3/4)^3

The key translation skill here is recognizing: “guessing” → fixed probability per trial, “exactly” → choose positions, and “independent questions” → multiply probabilities.

A Quick Checklist Before You Finalize

  • Did you answer what was asked (mean vs median vs probability)?
  • Did you keep the units (minutes, dollars, points)?
  • Did you sort the dataset if you used median?
  • Are probabilities between 0 and 1?
  • Did you write one final sentence that interprets the number?

Write the Final Answer Like This

Teachers often grade statistics word problems for interpretation, not just arithmetic. Use these sentence templates so your answer matches the story.

  • Mean: “The average ___ is ___ (units) per ___.”
  • Median: “The middle value is ___ (units), meaning half are below and half are above.”
  • Z-score: “This value is ___ standard deviations (above/below) the mean.”
  • Probability: “The chance of ___ is ___ (as a fraction/decimal/percent).”

If you can’t write a final sentence, it usually means you’re not sure what the number represents.

Practice Word Problems

  1. A runner’s times (in minutes) over 5 races are 22, 21, 25, 20, 22. Find the mean time and write one sentence interpreting it.
  2. Six homes sold for $180k, $200k, $210k, $220k, $500k, $650k. Which is a better “typical” price: mean or median? Explain.
  3. A test has μ = 70 and σ = 10. A student scores 85. Find the z-score and interpret in words.
  4. A survey reports the average wait time is 12 minutes. What extra information would you want to know to judge whether that’s reliable?

Tip: for #2, the outliers pull the mean; the median stays resistant. For #4, think about sample size and variability.

Common Mistakes

Doing “the math” too early

Start by identifying what the problem asks. Many errors come from computing the mean when the question wants the median.

Not stating the conclusion

In word problems, your final answer should be a sentence with units, not just a number.

Losing track of n

Mean and standard deviation both depend on n. Count how many data values there are.

Ignoring assumptions

If the problem says “assume normal,” use z-scores/areas. If it is just a list of values, use mean/median/mode.

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How to Solve Statistics Word Problems | Step-by-Step Translation Guide