Descriptive Statistics Calculator
Free online descriptive statistics calculator. Compute mean, median, mode, standard deviation, variance, quartiles, skewness, and more from your data.
Accepts numbers separated by commas, spaces, tabs, or new lines
How to Use the Descriptive Statistics Calculator
Enter your data values separated by commas, spaces, or new lines. The calculator computes all major descriptive statistics instantly.
Statistics Calculated
Measures of Central Tendency
| Statistic | Description |
|---|---|
| Mean | Arithmetic average of all values |
| Median | Middle value when data is sorted |
| Mode | Most frequently occurring value(s) |
Measures of Dispersion
| Statistic | Description |
|---|---|
| Standard Deviation | Average distance from the mean |
| Variance | Square of standard deviation |
| Range | Maximum minus minimum |
| IQR | Interquartile range (Q3 - Q1) |
| CV | Coefficient of variation (relative spread) |
Distribution Shape
| Statistic | Description |
|---|---|
| Skewness | Measure of asymmetry |
| Kurtosis | Measure of tail heaviness |
Understanding the Results
Mean vs. Median
- If mean ≈ median: Data is approximately symmetric
- If mean > median: Data is right-skewed (pulled by high values)
- If mean < median: Data is left-skewed (pulled by low values)
Standard Deviation
- Low SD: Data points cluster closely around the mean
- High SD: Data points spread widely from the mean
The 68-95-99.7 rule for normal distributions:
- ~68% of data falls within 1 SD of the mean
- ~95% of data falls within 2 SDs of the mean
- ~99.7% of data falls within 3 SDs of the mean
Skewness Interpretation
| Value | Interpretation |
|---|---|
| ≈ 0 | Symmetric |
| > 0 | Right-skewed (positive skew) |
| < 0 | Left-skewed (negative skew) |
| |skew| < 0.5 | Approximately symmetric |
| |skew| > 1 | Highly skewed |
Kurtosis Interpretation
| Value | Interpretation |
|---|---|
| ≈ 0 | Normal (mesokurtic) |
| > 0 | Heavy tails (leptokurtic) |
| < 0 | Light tails (platykurtic) |
Population vs. Sample Statistics
This calculator provides both:
| Type | Standard Deviation | Variance | When to Use |
|---|---|---|---|
| Population | σ = √(Σ(x-μ)²/N) | σ² | When data is the entire population |
| Sample | s = √(Σ(x-x̄)²/(n-1)) | s² | When data is a sample (most common) |
The sample statistics use (n-1) in the denominator (Bessel’s correction) to provide an unbiased estimate.
The Five-Number Summary
The five-number summary provides a quick overview of data distribution:
- Minimum: Smallest value
- Q1 (25th percentile): 25% of data falls below
- Median (50th percentile): Middle value
- Q3 (75th percentile): 75% of data falls below
- Maximum: Largest value
This summary is the basis for box plots (box-and-whisker diagrams).
Detecting Outliers
Using the IQR method:
- Lower fence: Q1 - 1.5 × IQR
- Upper fence: Q3 + 1.5 × IQR
Values beyond these fences are potential outliers.
Example Interpretation
For the sample data: 12, 15, 18, 22, 25, 28, 30, 35, 38, 42, 45, 48, 52, 55, 60
| Statistic | Value | Interpretation |
|---|---|---|
| Mean | 35.0 | Center of data |
| Median | 35.0 | Mean ≈ Median suggests symmetry |
| Std Dev | 15.2 | Moderate spread |
| Skewness | 0.0 | Symmetric distribution |
| IQR | 27 | Middle 50% spans 27 units |
When to Use Different Measures
Use Mean when:
- Data is symmetric
- No extreme outliers
- Interval or ratio scale
Use Median when:
- Data is skewed
- Outliers are present
- Ordinal scale acceptable
Use Mode when:
- Finding most common category
- Nominal scale data
- Describing typical case
Related Resources
- Measures of Central Tendency - Mean, median, mode
- Standard Deviation - Understanding spread
- Data Visualization - Graphing your data
- Histogram Generator - Visualize distributions
Want to learn the theory?
Our lessons explain the statistical concepts behind this calculator with clear examples.
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