Statistical Measures
Understanding how to analyze and summarize data using key statistical tools
Sample (Выборка)
Definition: A sample is a set of data collected from observations or experiments. Each number in the set is called a variant (варианта).
Example: Test scores from 10 students:
5
4
3
5
4
5
3
4
5
4
This collection of grades forms a sample of student performance.
Sample Size (Объём выборки)
Definition: The sample size is the count of numbers in the sample, denoted by n.
Example: For the sample {5, 4, 3, 5, 4, 5, 3, 4, 5, 4}:
n = 10
There are 10 variants in this sample
Why it matters: Sample size tells us how much data we collected. Larger samples usually give more reliable results!
Arithmetic Mean (Среднее арифметическое)
Definition: The arithmetic mean is the sum of all variants divided by the number of variants.
Formula:
Mean = (x₁ + x₂ + ... + xₙ) ÷ n
Or simply: Sum of all values ÷ Count of values
Step-by-Step Example:
Find the mean of: {3, 5, 7, 9, 6}
- Step 1: Add all values: 3 + 5 + 7 + 9 + 6 = 30
- Step 2: Count the values: n = 5
- Step 3: Divide: 30 ÷ 5 = 6
Answer: Mean = 6
Interactive visualization — available in the full lesson