Comprehensive Calculator Guide
This calculator gives a full summary of your data at once: count, sum, mean, median, mode, standard deviation, variance, minimum, maximum, range and quartiles, with a reading of what they mean. For seven salaries including one of SAR 25,000 it shows a mean of 10,143 against a median of 7,800, and flags the outlier.
Centre and spread
Mean, median and mode locate the centre; range, standard deviation, variance and IQR measure the spread. The SD here is the sample SD (n − 1). Compare mean and median for skew, and check values beyond 1.5 × IQR.
How to Use
- Enter the data.
- You can paste a spreadsheet column.
- Press “Summarise” to see every measure.
Formula Used
x̄ = Σx ÷ n | s = √(Σ(x − x̄)² ÷ (n − 1)) | quartiles = medians of the halves
Practical Examples
- Example 1
- Marks: mean 83.125, SD 11.32.
- Example 2
- Salaries: mean 10,142.86, median 7,800.
Important Tips
- Start here, then use the specific calculator.
- Report the median with skewed data.
- Check outliers first.
Common Mistakes to Avoid
- Reporting the mean with no spread.
- Mixing sample and population SD.
- Ignoring outliers.
Frequently Asked Questions
- What is descriptive statistics?
- Summarising data you have.
- Descriptive vs inferential?
- Inferential generalises to a population.
- Sample or population SD?
- Sample.