Normality Tests

Normality Tests — is your data bell-shaped? Paste a sample and find out in seconds. This app draws the histogram with the matching bell curve, plots a Q-Q chart, measures skew and kurtosis, and runs four formal normality tests — then gives you one plain-language verdict. Fully offline. A huge amount of statistics assumes your data follows a normal "bell" distribution: t-tests, ANOVA, linear regression and many more lean on it. Before you trust those tools, it pays to check. This app makes the check effortless: look at the shape, read the numbers, and let several tests vote on whether the bell assumption holds. No sign-up. No internet needed. No data collected. Just clear, instant statistics. WHAT YOU CAN DO • Tests — type or paste your numbers into a clean editor and instantly get the mean, SD, skew, excess kurtosis, and the result of four normality tests, topped with a single looks-normal / not-normal verdict. • Check — see the histogram with the fitted bell curve laid on top and a Q-Q plot, where points on the diagonal mean normal and an S-curve means skew or heavy tails. • Concept — learn what the bell curve is, how to read a histogram and Q-Q plot, what skew and kurtosis tell you, and what each formal test does — with offline, beautifully typeset formulas that never overlap. • Simulate — pick a shape (Normal, Right-skewed, Uniform, Heavy tails), set the sample size with a + / - steppered slider, and watch whether the tests catch what your eyes see. • Examples — load real-world samples (adult heights, household incomes and more) with one tap and see which pass and which fail. WHAT YOU GET • Skewness and excess kurtosis, the quickest shape clues. • Four tests at once: Jarque-Bera, Anderson-Darling, Kolmogorov-Smirnov (Lilliefors) and a skew & kurtosis z-test. • A clear verdict with how many tests reject normality. • A histogram + bell curve and a Q-Q plot so you can judge with your own eyes. WHY YOU'LL LIKE IT • See AND test — pictures and p-values together, not one or the other. • Several tests vote — more robust than relying on a single one. • Fully offline — every chart, statistic and formula works with no connection. • Hands-on — type exact data, or build a sample with a shape picker and + / - stepper. • Clean "Navy & Azure" design, easy on the eyes. • Privacy-friendly — your data stays on your device. A reminder: with small samples the formal tests are weak, so always trust the picture too, not just the numbers. Whether you are checking an assumption before a t-test, teaching what "normal" really means, or just curious about a dataset's shape, Normality Tests gives you the full answer in seconds. Download it, paste your data, and see if it is really bell-shaped.