Box Plots and Quartiles: Five-Number Summary and Outliers
How to find quartiles and the interquartile range, draw a box-and-whisker plot, and spot outliers with the 1.5 × IQR rule.
Tagged: statistics
6 guides.
Confidence Intervals Explained (Without the Jargon)
What a 95% confidence interval really means, how to calculate one from a sample mean, and how sample size changes the margin of error.
Line of Best Fit: Linear Regression and Correlation Explained
How to find the least-squares line of best fit, what the correlation coefficient r and r² mean, and why correlation is not causation.
How to Calculate Mean, Median and Mode
Find the mean, median, mode and range of a data set step by step, learn which average to use, and see how outliers affect each one.
Standard Deviation and Variance Explained Step by Step
What standard deviation measures, how to calculate it for a population or a sample, why samples divide by n − 1, and a full worked example.
The Normal Distribution and Z-Scores Made Simple
Understand the bell curve, the 68–95–99.7 rule, z-scores and how to find normal probabilities, with worked examples on test scores and heights.