What is Statistical series? — Mathematics

Definition 8.1 High School Mathematics · Chapter 8 — Descriptive Statistics

A statistical series is a list of values $x_1, x_2, \dots, x_N$ observed on a population of size $N$ . When a value $x$ appears $n$ times, $n$ is its count and the quotient

f = \frac{n}{N}

is its frequency (often expressed as a percentage). The frequencies of all values add up to $1$ .

The bar chart of the quiz grades: one bar per value, with height equal to the count.

Examples

Example 8.2

The grades of $20$ students on a $5$ -point quiz:

grade $x$	$0$	$1$	$2$	$3$	$4$	$5$
count $n$	$1$	$2$	$4$	$6$	$5$	$2$
frequency $f$	$0.05$	$0.10$	$0.20$	$0.30$	$0.25$	$0.10$

Check: $1 + 2 + 4 + 6 + 5 + 2 = 20$ and the frequencies sum to $1$ .

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