Skip to content

Introduction to Statistics

Calculate measures of central tendency and create basic data displays.

Written and reviewed by the Study Mondo Education TeamLast updated
🎯⭐ INTERACTIVE LESSON

Try the Interactive Version!

Learn step-by-step with practice exercises built right in.

Start Interactive Lesson →

Introduction to Statistics

Measures of Central Tendency

Mean (Average)

Mean=Sum of valuesNumber of values\text{Mean} = \frac{\text{Sum of values}}{\text{Number of values}}

Median

Middle value when data is ordered. For even count, average the two middle values.

Mode

Most frequently occurring value.

Example

Data: 5,8,3,8,12,6,85, 8, 3, 8, 12, 6, 8

Ordered: 3,5,6,8,8,8,123, 5, 6, 8, 8, 8, 12

  • Mean: 3+5+6+8+8+8+127=507≈7.14\frac{3+5+6+8+8+8+12}{7} = \frac{50}{7} \approx 7.14
  • Median: 88 (4th value out of 7)
  • Mode: 88 (appears 3 times)

Measures of Spread

  • Range: Max−Min=12−3=9\text{Max} - \text{Min} = 12 - 3 = 9
  • IQR (Interquartile Range): Q3−Q1Q_3 - Q_1

Box Plots

Show the five-number summary: Min, Q1, Median, Q3, Max

Stem-and-Leaf Plots

Show data values organized by their leading digits.

Data: 23, 25, 31, 34, 37, 42, 45

StemLeaf
23 5
31 4 7
42 5

Choosing the Right Display

Data TypeDisplay
CategoricalBar graph, circle graph
NumericalHistogram, dot plot, box plot
Comparing two groupsDouble bar graph, side-by-side box plots

Key idea: The mean is affected by outliers; the median is not. Choose the median for skewed data.

Explain using:

⚠️ Common Mistakes: Introduction to Statistics

Avoid these 3 frequent errors

🌍 Real-World Applications: Introduction to Statistics

See how this math is used in the real world

📝 Worked Example: Solving a Quadratic by Factoring

Problem:

Solve x2−5x+6=0x^2 - 5x + 6 = 0.

2Factor the quadratic
3Set each factor equal to zero
🎴

Practice with Flashcards

Rate this topic's cards with spaced repetition. Cards join your deck when you finish a topic's lesson and take its exit quiz.

📖

Browse All Topics

Explore more Pre-Algebra topics

❓ Frequently Asked Questions

What is Introduction to Statistics?▾
Calculate measures of central tendency and create basic data displays.
How can I study Introduction to Statistics effectively?▾
Start by reading the study notes and working through the examples on this page. Then use the flashcards to test your recall. Regular review and active practice are key to retention.
Is this Introduction to Statistics study guide free?▾
Yes — all study notes, flashcards, and practice problems for Introduction to Statistics on Study Mondo are free to access. No account is needed.
What course covers Introduction to Statistics?▾
Introduction to Statistics is part of the Pre-Algebra course on Study Mondo, specifically in the Basic Statistics section. You can explore the full course for more related topics and practice resources.