Descriptive statistics calculator
Paste a column of numbers and get every summary statistic at once, with the boxplot and histogram drawn on a shared scale so you can see the shape while you read the numbers.
Center
Spread
Five-number summary
Outliers
Shape: mean above median, so the tail runs right.
What to look at first
Compare the mean and the median before anything else. If they are close, the distribution is roughly symmetric and the mean is a fair summary of center. If the mean sits well above the median, the tail runs right and something large is pulling the average up. That single comparison tells you more about a data set than any other pair of numbers, and it is why mean vs median is worth understanding properly.
Then check the flagged values. A point outside the fences is not automatically an error, it is a value worth explaining. In a test-score data set it might be a student who was absent for the unit; in a measurement data set it might be a typo. The 1.5 x IQR rule flags candidates, it does not make the decision for you.
Use the sample standard deviation
Both are shown, and in AP Statistics you almost always want the sample version, the one that divides by n minus 1. Your data is nearly always a sample drawn from a larger population, and dividing by n minus 1 corrects a bias that would otherwise make your estimate of spread too small. Use the population figure only when your data really is every member of the group you care about. The standard deviation by hand guide walks the arithmetic if you need to show the work.
Frequently asked questions
Does this calculate sample or population standard deviation?
Both, side by side. The sample standard deviation divides by n minus 1 and is the one you want almost every time in AP Statistics, because your data is a sample from a larger population. The population standard deviation divides by n and applies only when your data is the entire population. Mixing these up is one of the most common ways to lose a point.
Which quartile convention does it use?
The median-excluded convention, which is what the TI-84 uses and what AP Statistics expects. When the data set has an odd number of values, the median itself is left out of both halves before finding Q1 and Q3. Other software, including some spreadsheet functions, uses a different rule and will give slightly different quartiles on the same data.
How are outliers decided?
By the 1.5 times IQR rule. Any value below Q1 minus 1.5 times the IQR, or above Q3 plus 1.5 times the IQR, is flagged and drawn as a red circle on the boxplot. That is a rule for flagging values worth a second look, not proof that a value is a mistake.
Is my data sent anywhere?
No. Everything is computed in your browser. Nothing you paste leaves your device, nothing is stored, and there is no account.
Embed this interactive on your class site (free)
Paste this into any webpage, LMS page, or class site. Free for educational use; the small credit link stays on.