Descriptive Statistics Calculator
Free descriptive statistics calculator. Mean, median, mode, variance, SD, SEM, CV, skewness, kurtosi
Why This Statistical Analysis Matters
Why: Statistical calculator for analysis.
How: Enter inputs and compute results.
All-in-One Descriptive Stats โ Mean, Median, Mode, SD, Skewness, Kurtosis, Quartiles
Comprehensive summary: central tendency, dispersion, shape, and position. Histogram, box plot, step-by-step breakdown.
Real-World Scenarios โ Click to Load
Data Input
Distribution Histogram
Box Plot (5-Number Summary)
Shape: Skewness & Kurtosis vs Normal (0)
Calculation Breakdown
For educational and informational purposes only. Verify with a qualified professional.
Key Takeaways
- โข Central tendency: Mean, median, mode โ describe the "center" of your data
- โข Dispersion: Range, variance, SD, SEM, MAD, CV, IQR โ measure spread
- โข Shape: Skewness (asymmetry), kurtosis (tail heaviness) โ describe distribution shape
- โข Position: Quartiles, percentiles โ indicate where values fall relative to the whole
- โข Population vs sample: Use sample variance (nโ1) when estimating from a sample; population when you have the full dataset
Did You Know?
How It Works
1. Central Tendency
Mean = sum/n. Median = 50th percentile. Mode = most frequent value.
2. Dispersion
Variance = ฮฃ(xโฮผ)ยฒ/(nโ1) for sample. SD = โvariance. SEM = SD/โn.
3. Shape
Skewness = mโ/mโ^1.5. Kurtosis = mโ/mโยฒ โ 3 (excess kurtosis).
4. Quartiles & Percentiles
Linear interpolation between adjacent values. Q1 = P25, Q2 = P50 (median), Q3 = P75.
5. Population vs Sample
Sample variance uses nโ1 (Bessel correction). Population uses n.
Expert Tips
Report Both Mean and Median
If they differ significantly, your data is skewed. Report both for transparency.
Use SEM for Inference
When reporting mean ยฑ error, use SEM. For spread of data, use SD.
Check Normality
Q-Q plot and skewness/kurtosis help. Many parametric tests assume normality.
Weighted Data
Use value,weight format per line for weighted mean. Default: equal weights.
Why Use This Calculator vs. Other Tools?
| Feature | This Calculator | Excel | R |
|---|---|---|---|
| All stats in one place | โ | โ ๏ธ Multiple functions | โ summary() |
| Skewness & kurtosis | โ | โ ๏ธ SKEW, KURT | โ moments |
| Histogram + box plot | โ | โ ๏ธ Manual | โ |
| Population vs sample | โ | โ ๏ธ | โ |
| Copy & share results | โ | โ | โ |
| AI-powered interpretation | โ | โ | โ |
Frequently Asked Questions
When to use mean vs median?
Mean for symmetric data. Median for skewed data or when outliers are present. Report both when in doubt.
What is SEM?
Standard error of the mean = SD/โn. Measures how precisely the sample mean estimates the population mean.
What does skewness mean?
Skewness > 0: right tail longer. Skewness < 0: left tail longer. Skewness โ 0: symmetric.
What is excess kurtosis?
Kurtosis โ 3. Normal distribution has excess kurtosis 0. Positive: heavy tails. Negative: light tails.
Population vs sample variance?
Sample: divide by nโ1 (unbiased estimator). Population: divide by n. Use sample when you have a subset.
What is MAD?
Median absolute deviation โ median of |x โ median|. Robust to outliers.
What is CV?
Coefficient of variation = (SD/mean)ร100%. Allows comparing variability across different scales.
Formulas Reference
Mean: ฮผ = ฮฃx/n
Variance (sample): sยฒ = ฮฃ(xโฮผ)ยฒ/(nโ1)
SEM = s/โn
CV = (s/mean)ร100%
Skewness = mโ/mโ^1.5, Kurtosis = mโ/mโยฒ โ 3
IQR = Q3 โ Q1
Descriptive Stats by the Numbers
Official Data Sources
Disclaimer: Population vs sample variance affects SD and variance. Use sample when estimating from a subset; population when you have full data. This tool is for educational and professional reference purposes.
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