Statistics Cheat Sheet

Key Definitions

• Mean: The average of a set of numbers.

• Median: The middle value when data is arranged in order.

• Mode: The value that appears most frequently in a data set.

• Range: The difference between the highest and lowest values.

• Variance: The average of the squared differences from the Mean.

• Standard Deviation (SD): A measure of the amount of variation or dispersion in a set of values.

Important Concepts

Data Types

• Qualitative: Non-numeric data (e.g., colors, names).

• Quantitative: Numeric data (e.g., height, weight).

• Discrete: Countable values (e.g., number of students).

• Continuous: Measurable values (e.g., temperature).

Measures of Central Tendency

• Mean, Median, Mode are used to summarize data sets.

Probability Basics

• Probability (P): Likelihood of an event occurring.

• P(Event) = (Number of favorable outcomes) / (Total outcomes)

Key Formulas

• Mean:

• Σx: Sum of all values

• n: Number of values

• Variance:

• Standard Deviation:

Common Mistakes to Avoid

Common Mistake: Confusing Mean with Median; remember, Mean is affected by outliers.

Memory Tricks

Tip: "M&M's" — Mean, Median, Mode — to remember the three measures of central tendency.

Key Diagrams

          Mean
           |
           |       Median
           |         |
           |         |       Mode
           |         |         |
-----------|---------|---------|---------
           |         |         |
           |         |         |
          Max       Median     Mode