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Use this P-value calculator to compute exact tail probabilities for common test statistics. This calculator supports Z-scores, t-scores, chi-square (χ²), and F-scores. To use it, select your test statistic from the dropdown menu. Then, enter your degrees of freedom (if required) and observed test statistic value. Click Calculate to see the result. [Read more…] about P-Value Calculator

Use this T Test Calculator to perform a 1-sample, 2-sample, or paired t-test and assess your sample means. All these t-test calculator will find p-values and construction confidence intervals. Just scroll down to find the t-test you need and click to expand it. Simply enter your data into the table. Or copy and paste from a spreadsheet and the table will add rows as needed. You can enter up to 300 data rows, and the calculator automatically ignores incomplete or invalid rows. The editable headers are used in the statistical results. [Read more…] about T Test Calculator

Use this chi-square calculator to test relationships between categorical variables. It computes the Pearson’s chi-square statistic by comparing your observed counts to the values you would expect if there were no association between categories. The results include the overall χ² value, degrees of freedom, p-value, and an APA-style results format for publications. [Read more…] about Chi-Square Calculator

Use this percentile calculator to find a specific percentile in your dataset and its quartiles. It also displays a table with the 10th, 25th, 50th, 75th, and 90th percentiles so you can gauge your data’s distribution at a glance. [Read more…] about Percentile Calculator

The Percent Error Calculator determines how accurate a measurement is by comparing an observed value to a true value. It calculates the absolute difference relative to the true value and expresses it as percent error. For example, measuring 8.5 when the true value is 10 yields a 15% error. [Read more…] about Percent Error Calculator

The Percentage Change Calculator quantifies how much one value changes relative to another. It expresses the result as a percent increase or decrease from the initial value. For example, going from 5 books to 10 books represents a 100% increase. Conversely, going from 10 books to 5 represents a 50% decrease. [Read more…] about Percentage Change Calculator

This variance calculator makes it easy to measure how spread out your data are. Just enter your numbers in the text box, separated by commas or spaces. Then choose whether you want to calculate the sample variance or the population variance. [Read more…] about Variance Calculator

This permutation calculator finds the number of ways to arrange a sample of items from a larger set when the order matters. Enter the total number of objects (n) and the number of items in your arrangement (r). For example, the permutations calculator can tell you how many ways you can arrange 4 books from a shelf of 10 books. If the order items in the sample does NOT matter, use the Combination Calculator instead. [Read more…] about Permutation Calculator

This combination calculator finds the number of ways to choose a sample of items from a larger set when order does not matter. Enter the total number of objects (n) and the number of items in your sample (r). For example, the combination calculator can tell you how many ways you can choose 4 books from a shelf of 10 books. If the order items in the sample does matter, use the Permutation Calculator instead. [Read more…] about Combination Calculator

This correlation coefficient calculator measures the strength and direction of a linear relationship between two variables. Simply enter paired data into the table. Or copy and paste from a spreadsheet and the table will add rows as needed. You can enter up to 300 data rows, and the calculator will automatically ignore incomplete or invalid rows. The editable headers are used for the axis labels in the graph. [Read more…] about Correlation Coefficient Calculator

This Poisson distribution calculator finds the probability of a specific number of events occurring within a fixed interval of time or space, based on a known average rate. Just enter the average rate (λ) and the number of events you’re interested in (x). For example, the Poisson distribution calculator can tell you the probability of receiving 3 emails in an hour if you typically receive 5 emails per hour. [Read more…] about Poisson Distribution Calculator

Use this binomial distribution calculator to find the probability of a specific number of events occurring in a fixed number of trials. Just enter the probability of a single event (p), the number of trials (n), and the number of events you’re interested in (x). For example, the binomial distribution calculator can tell you the probability of getting 5 heads in 6 coin tosses. [Read more…] about Binomial Distribution Calculator

This confidence interval calculator finds the confidence interval for the mean–just enter several summary values and choose the method. Below the calculator are additional instructions and examples for using it. [Read more…] about Confidence Interval Calculator

This mean, median, and mode calculator makes it easy to find the center of your data. Just enter your numbers in the text box, separated by commas or spaces. [Read more…] about Mean Median Mode Calculator

This standard deviation calculator makes it easy to measure how spread out your data are. Just enter your numbers in the text box, separated by commas or spaces. Then choose whether you want to calculate the sample standard deviation or the population standard deviation. [Read more…] about Standard Deviation Calculator