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📋 Statistics from a frequency table

Type your frequency table (value and fᵢ) and get the mean, median, mode, range and standard deviation read from the cumulative frequency, step by step.

Value (xᵢ)Frequency (fᵢ)
Examples:

Data read, sorted: 0 · 0 · 0 · 0 · 1 · 1 · 1 · 1 · 1 · 1 · 2 · 2 · 2 · 2 · 2 · 2 · 2 · 2 · 3 · 3

Data (N)

20

Mean

1.4

Median

1.5

Mode

2

Range

3

Standard deviation

√21/5 ≈ 0.92

02468fᵢ0: 4401: 6612: 8823: 223Me

Frequency table

xᵢfᵢFᵢhᵢ%
0440.220 %
16100.330 %
28180.440 %
32200.110 %
N20

Mean (x̄)

  1. Add up all the data: each value times how often it appears.
  2. 0·4 + 1·6 + 2·8 + 3·2 = 28
  3. Divide by the number of data values, N = 20: x̄ = 28 / 20 = 1.4

Median (Me)

  1. With the data sorted, the median is the middle value. There are N = 20 values, which is even.
  2. There are two middle values, in positions 10 and 11: 1 and 2.
  3. To find a position, look for the first row whose cumulative frequency (Fᵢ) reaches that number.
  4. Me = (1 + 2) / 2 = 1.5

Mode (Mo)

  1. The most repeated value is 2, 8 times: Mo = 2.

Range

  1. Maximum − minimum = 3 − 0 = 3

Variance and standard deviation

  1. How far the data are from the mean, on average. For each value: its distance to the mean, squared, times its frequency.
  2. σ² = Σ fᵢ·(xᵢ − x̄)² / N = (4·(0 − 1.4)² + 6·(1 − 1.4)² + 8·(2 − 1.4)² + 2·(3 − 1.4)²) / 20 = 0.84
  3. σ = √σ² = √21/5 ≈ 0.92
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