Interactives
Some statistics ideas refuse to come through a static page. These are built to be dragged: each one turns the concept students find hardest into something you can feel respond. Free, no login, works on phones. To put one on a class page, copy the iframe from widgets.
Which statistical test should I use?Answer two or three questions about your data and design, and the right procedure falls out with the calculator to run it.Descriptive statistics calculatorPaste a column of numbers and get every summary statistic at once, with the boxplot and histogram drawn on a shared scale.Descriptive statistics sandboxDrag data points on a dotplot and watch the mean chase outliers while the median holds still. The boxplot, SD, and IQR update live.Sampling distribution and CLT visualizerPick a lumpy parent population, slide the sample size, draw thousands of samples, and watch the distribution of sample means turn normal and narrow by root n.Normal curve area and z-score explorerDrag the boundaries on a normal curve to shade a tail or a middle band, and read the probability, the z-scores, and the percentiles as you go. Lock the z-scores and the area holds while the mean and SD move.Confidence interval coverage simulatorDraw hundreds of samples, build a confidence interval from each, and count how many actually capture the true parameter. What 95 percent confidence means, as a tally rather than a sentence.Type I error, Type II error, and power visualizerSlide the true parameter, the sample size, and alpha, and watch the two error regions trade off against each other. Power is the area you are trying to grow, and it is drawn.Regression influential-point explorerDrag one high-leverage point and watch the least-squares line, r, and the residual plot swing. Influence, made physical.